Yuri Khachaturov, Secretary General of the Collective Security Treaty Organization (CSTO), Armenian President Serzh Sarksyan, Belarussian President Alexander Lukashenko, Kyrgyz President Sooronbai Jeenbekov, Russian President Vladimir Putin and Tajik President Imomali Rakhmon pose for a family photo during a meeting of the organisation's heads of state in Minsk, Belarus November 30, 2017. REUTERS/Vasily Fedosenko 

Kyrgyz President Sooronbai Jeenbekov, Tajik President Imomali Rakhmon, Russian President Vladimir Putin and Belarussian President Alexander Lukashenko arrive for a meeting of the Collective Security Treaty Organization (CSTO) heads of state in Minsk, Belarus November 30, 2017. REUTERS/Vasily Fedosenko 

Belarussian President Alexander Lukashenko and Tajik President Imomali Rakhmon pose for a photo during a meeting of the Collective Security Treaty Organization (CSTO) heads of state in Minsk, Belarus November 30, 2017. REUTERS/Vasily Fedosenko 

Tajik President Imomali Rakhmon arrives for a meeting of the Collective Security Treaty Organization (CSTO) heads of state in Minsk, Belarus November 30, 2017. REUTERS/Vasily Fedosenko 

A member of a local electoral commission counts ballots after a parliamentary election at a polling station in the Tajik capital Dushanbe March 1, 2015. Tajikistan voted on Sunday to elect a new parliament that will likely be dominated by the party of President Imomali Rakhmon who has ruled the Central Asian nation since 1992 and is backed by Moscow, which has thousands of troops stationed there. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A member of a local electoral commission empties a ballot box after a parliamentary election at a polling station in the Tajik capital Dushanbe March 1, 2015. Tajikistan voted on Sunday to elect a new parliament that will likely be dominated by the party of President Imomali Rakhmon who has ruled the Central Asian nation since 1992 and is backed by Moscow, which has thousands of troops stationed there. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

Tajikistan President Imomali Rakhmon (3rd R) and China's President Xi Jinping (L) attend a meeting at the Great Hall of the People in Beijing, November 7, 2014. REUTERS/Jason Lee (CHINA - Tags: POLITICS BUSINESS) 

Tajikistan's President Imomali Rakhmon (L) shakes hands with China's President Xi Jinping before a meeting at the Great Hall of the People in Beijing November 7, 2014. REUTERS/Jason Lee (CHINA - Tags: POLITICS) 

A man walks out of a voting booth at a polling station during the presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A man casts his ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

Elderly men (R) visit a polling station to vote during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A man casts his ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

People are seen through a window as they register to vote at a polling station, during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A man casts his ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

People are seen through a window as they register to vote at a polling station, during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A woman casts her ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A man casts his ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

Elderly men pray outside a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS) 

A man casts his ballot at a polling station during a presidential election in Dushanbe, November 6, 2013. Tajikistan on Wednesday started voting in a presidential election in which incumbent Imomali Rakhmon is set to win a new seven-year term to lead the Central Asian country that faces security threats from neighboring Afghanistan. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS TPX IMAGES OF THE DAY) 

An electoral official places a ballot box during the preparations for the upcoming presidential election at a polling station in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

Electoral officials carry a ballot box during the preparations for the upcoming election at a polling station in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

A girl begs for money in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

Police officers walk outside a polling station in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

People visit a street market in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

Women sell curdled milk at a street market in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

People stand in front of an information board with job vacancies in Dushanbe November 1, 2013. Tajikistan's President Imomali Rakhmon is expected to win a new seven-year term in an election on Nov. 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

An employee works on a roof, with a billboard displaying Tajikistan's President Imomali Rakhmon seen in the background, in Dushanbe, November 1, 2013. Rakhmon is expected to win a new seven-year term in an election on November 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

Men walk in a street, with a board displaying Tajikistan's President Imomali Rakhmon seen on a building in the background, in Dushanbe, November 1, 2013. Rakhmon is expected to win a new seven-year term in an election on November 6, extending his rule in the former Soviet republic in Central Asia to nearly three decades. Picture taken November 1, 2013. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS ELECTIONS SOCIETY) 

Uzbekistan's President Islam Karimov, Kyrgyzstan's President Almazbek Atambayev, Russia's President Vladimir Putin, China's President Hu Jintao, Kazakhstan's President Nursultan Nazarbayev and Tajikistan's President Imomali Rakhmon (L-R) pose for a family photo at the start of the Shanghai Cooperation Organisation (SCO) summit at the Great Hall of the People in Beijing June 6, 2012. A bloc bringing together China, Russia and central Asian states wants to play a bigger role in Afghanistan, Hu said in an interview published on Wednesday, as group leaders gathered for an annual summit. REUTERS/Mark Ralston/Pool (CHINA - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (L) greets his Afghan counterpart Hamid Karzai during a meeting in Dushanbe, March 25, 2012. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS) 

(From L to R) Afghan President Hamid Karzai, Tajikistan President Imomali Rakhmon and Iranian President Mahmoud Ahmadinejad pose for pictures during a meeting in Dushanbe, March 25, 2012. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS) 

(From L to R) Pakistan's President Asif Ali Zardari, Iran's President Mahmoud Ahmadinejad, Tajikistan's President Imomali Rakhmon and Afghan President Hamid Karzai pose for pictures during a meeting in Dushanbe, March 25, 2012. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS) 

Afghan President Hamid Karzai (L) greets his Pakistani counterpart Asif Ali Zardari (C) next to Tajikistan's President Imomali Rakhmon during a meeting in Dushanbe, March 25, 2012. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS) 

German Chancellor Angela Merkel (R) and Tajikistan's President Imomali Rakhmon address the media after talks in Berlin December 14, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS) 

German Chancellor Angela Merkel (R) and Tajikistan's President Imomali Rakhmon arrive for a news conference after talks in Berlin December 14, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS) 

German Chancellor Angela Merkel (R) and Tajikistan's President Imomali Rakhmon address the media after talks in Berlin December 14, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS) 

German Chancellor Angela Merkel (R) and Tajikistan's President Imomali Rakhmon address the media after talks in Berlin December 14, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS) 

German Economy Minister Philipp Roesler (L) welcomes Tajik President Imomali Rakhmon before talks in Berlin December 13, 2011. REUTERS/Tobias Schwarz (GERMANY - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (R) and his Iranian counterpart Mahmoud Ahmadinejad tour Sangtuda 2 Hydroelectric Power Plant on the Vakhsh river September 5, 2011. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS ENERGY) 

Tajikistan's President Imomali Rakhmon (R) and his Iranian counterpart Mahmoud Ahmadinejad (C) arrive at Sangtuda 2 Hydroelectric Power Plant on the Vakhsh river September 5, 2011. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS ENERGY) 

Tajikistan's President Imomali Rakhmon (R) and his Iranian counterpart Mahmoud Ahmadinejad (2nd R) attend a welcoming ceremony upon their arrival at Sangtuda 2 Hydroelectric Power Plant on the Vakhsh river September 5, 2011. REUTERS/Stringer (TAJIKISTAN - Tags: POLITICS ENERGY) 

Tajik President Imomali Rakhmon (R) talks with his Ukrainian counterpart Viktor Yanukovich during a CIS summit in Dushanbe September 3, 2011. REUTERS/Andrey Mosienko/Pool (TAJIKISTAN - Tags: POLITICS) 

Kazakh President Nursultan Nazarbayev (R) greets his Tajik counterpart Imomali Rakhmon during a CIS summit in Dushanbe September 3, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (C) holds hands with Pakistan's President Asif Ali Zardari and Afghanistan's President Hamid Karzai (L) during a summit in Dushanbe September 2, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (L) listens next to Afghanistan's President Hamid Karzai (R) during a summit in Dushanbe September 2, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (2nd L), Russia's President Dmitry Medvedev (2nd R), Pakistan's President Asif Ali Zardari (R) and Afghanistan's President Hamid Karzai smile as they stand together during a summit in Dushanbe September 2, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (C), Russia's President Dmitry Medvedev (R) and Pakistan's President Asif Ali Zardari walk next to each other during a summit in Dushanbe September 2, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (2nd L), Russia's President Dmitry Medvedev (2nd R), Pakistan's President Asif Ali Zardari (L) and Afghanistan's President Hamid Karzai stand together during a summit in Dushanbe September 2, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajik President Imomali Rakhmon (R) talks with his Pakistani counterpart Asif Ali Zardari during a meeting in Dushanbe September 1, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (R) shakes hands with his Pakistani counterpart Asif Ali Zardari during their meeting in Dushanbe, September 1, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (R) talks with his Afghan counterpart Hamid Karzai during their meeting in Dushanbe, September 1, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (R) shakes hands with his Afghan counterpart Hamid Karzai during their meeting in Dushanbe, September 1, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

Tajikistan's President Imomali Rakhmon (R) shakes hands with his Afghan counterpart Hamid Karzai during their meeting in Dushanbe, September 1, 2011. REUTERS/Nozim Kalandarov (TAJIKISTAN - Tags: POLITICS) 

(From L to R, first row) Tajikistan's President Imomali Rakhmon, Pakistan's President Asif Ali Zardari, Iranian President Mahmoud Ahmadinejad, Afghan President Hamid Karzai, Turkey's President Abdullah Gul, Azerbaijan's President Ilham Aliyev, Kyrgyz President Roza Otunbayeva, Iraq's President's Jalal Talabani (from L to R, second row) Turkish Cypriot Deputy Undersecretary Aytug Plumer, Qatar's Finance Minister Yousef Kamal, Kazakhstan's Prime Minister Karim Masimov, Syrian Economy Minister Lamia Asi and ECO Secretary General Mohammad Yahya Maroofi pose for the family photo of the 11th Economic Cooperation Organization (ECO) Summit in Istanbul December 23, 2010. REUTERS/Umit Bektas (TURKEY - Tags: POLITICS) 

(L-R) Azeri President Ilham Aliyev, Armenian President Serzh Sargsyan, Belarussian President Alexander Lukashenko, Kazakh President Nursultan Nazarbayev, Kyrgyz President Roza Otunbayeva, Moldovan Economics Minister Valery Lazer, Russian President Dmitry Medvedev, Tajik President Imomali Rakhmon, Turkmen Deputy Prime Minister Nazarguly Shagulyev, Uzbek President Islam Karimov, Ukrainian President Viktor Yanukovich and Executive Secretary of of the Commonwealth of Independent States (CIS) Sergei Lebedev pose for a picture during their meeting in Moscow's Kremlin, December 10, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (L) and his Tajik counterpart Imomali Rakhmon attend a joint news conference during the Commonwealth of Independent States (CIS) summit in Moscow's Kremlin, December 10, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (R) and his Tajik counterpart Imomali Rakhmon attend a joint news conference during the Commonwealth of Independent States (CIS) summit in Moscow's Kremlin, December 10, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (2nd L), Kazakh President Nursultan Nazarbayev (L), Tajik President Imomali Rakhmon (R, front), Azeri President Ilham Aliyev (L, in the background), Ukrainian President Viktor Yanukovich (R) and Uzbek President Islam Karimov (2nd R, in the background) walk to take part in a meeting of the Commonwealth of Independent States (CIS) leaders in Moscow's Kremlin, December 10, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (2nd R), Kazakh President Nursultan Nazarbayev (L), Kyrgyz President Roza Otunbayeva (R), Uzbek President Islam Karimov (L in the background) and Tajik President Imomali Rakhmon (R in the background) walk in to take part in the Collective Security Treaty Organisation (CSTO) summit in Moscow's Kremlin, December 10, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Tair Mansurov, secretary general of the Euro-Asian economic union of former Soviet republics (EurAsEC), Armenian President Serzh Sarksyan, Tajik President Imomali Rakhmon, Russian President Dmitry Medvedev, Kyrgyz President Roza Otunbayeva, Kazakh President Nursultan Nazarbayev and Belarussian President Alexander Lukashenko (R-L) pose for a photo during the Eurasian Economic Community Interstate Council in Moscow's Kremlin, December 9, 2010. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS)