The emblem of the STC is seen between weapons held by Yemeni government soldiers at the headquarters of the separatist Southern Transitional Council in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

A Yemeni government soldier holds a weapon as he stands by an emblem of the STC at the headquarters of the separatist Southern Transitional Council in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

A pro-government Yemeni soldier walks past an armored military vehicle used by UAE-backed southern separatist fighters in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

A pro-government Yemeni soldier mans a checkpoint in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidhaya 

A pro-government Yemeni soldier walks near a damaged military vehicle used by UAE-backed southern separatist fighters at the headquarters of the separatist Southern Transitional Council, taken by government forces during the recent clashes, in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

Armored military vehicles used by UAE-backed southern separatist fighters are seen outside the headquarters of the separatist Southern Transitional Council, taken by government forces during the recent clashes, in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

Armored military vehicles used by UAE-backed southern separatist fighters are seen outside the headquarters of the separatist Southern Transitional Council, taken by government forces during the recent clashes, in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

People inspect the wreckage of an armored vehicle belonging to UAE-backed southern separatist fighters, burnt during the recent clashes, in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

People gather by the wreckage of an armored vehicle belonging to UAE-backed southern separatist fighters, burnt during the recent clashes in Ataq, Yemen August 27, 2019. REUTERS/Ali Owidha 

Tribal fighters loyal to the Yemeni government ride on the back of a truck on a road taken by government forces during recent clashes with southern separatists west of Ataq of the Shabwa province, Yemen August 26, 2019. REUTERS/Ali Owidha 

Pro-government soldiers patrol an area taken by government forces during recent clashes with southern separatists west of Ataq of the Shabwa province, Yemen August 26, 2019. REUTERS/Ali Owidha 

A soldier stands at a military post taken by government forces during recent clashes with southern separatists west of Ataq of the Shabwa province, Yemen August 26, 2019. REUTERS/Ali Owidha 

Boys gather near the wreckage of car destroyed last year by a U.S. drone air strike targeting suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY TPX IMAGES OF THE DAY) 

Tribesmen stand on the rubble of a building destroyed by a U.S. drone air strike, that targeted suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. Abdulrahman al-Awlaki, the son of slain U.S.-born cleric Anwar al-Awlaki, and six al Qaeda militants, were killed in a strike on this building on October 14, 2011, tribal elders said. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. Abdulrahman al-Awlaki was 16 years old and also a U.S. citizen. His father had been killed in a drone two weeks earlier, in September 2011. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

Tribesmen stand on the rubble of a building destroyed by a U.S. drone air strike, that targeted suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. Abdulrahman al-Awlaki, the son of slain U.S.-born cleric Anwar al-Awlaki, and six al Qaeda militants, were killed in a strike on this building on October 14, 2011, tribal elders said. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. Abdulrahman al-Awlaki was 16 years old and also a U.S. citizen. His father had been killed in a drone two weeks earlier, in September 2011. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

Boys gather near a building damaged last year by a U.S. drone air strike targeting suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

A tribesman walks near a building damaged last year by a U.S. drone air strike targeting suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

Boys gather near a building damaged by a U.S. drone air strike, that targeted suspected al Qaeda militants last year in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

Tribesmen stand on the rubble of a building destroyed by a U.S. drone air strike, that targeted suspected al Qaeda militants in Azan of the southeastern Yemeni province of Shabwa February 3, 2013. Abdulrahman al-Awlaki, the son of slain U.S.-born cleric Anwar al-Awlaki, and six al Qaeda militants, were killed in a strike on this building on October 14, 2011, tribal elders said. U.S. drones have launched almost daily raids on suspected al Qaeda militants in Yemen over the past two weeks, and air strikes have aggravated discontent among Yemenis, who say the strikes pose a threat to civilians. Abdulrahman al-Awlaki was 16 years old and also a U.S. citizen. His father had been killed in a drone two weeks earlier, in September 2011. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY SOCIETY) 

Flames rise from Yemen's main gas pipeline after it was blown up by unknown attackers early August 21, 2012. Yemen LNG said on Tuesday that an explosion caused by sabotage has hit a gas pipeline feeding the country's only liquefied natural gas (LNG) export terminal. REUTERS/Stringer (YEMEN - Tags: ENERGY CRIME LAW BUSINESS) 

Smoke billows from an oil pipeline blown up in the southern Yemeni province of Shabwa November 2, 2010. Suspected al Qaeda militants blew up the pipeline on Tuesday, local officials said, the same day the country launched a hunt for those responsible for a plot to mail bombs to the United States. The pipeline in the province of Shabwa was operated by a South Korean firm, officials said, but declined to give further details. It was not clear if exports would be affected. REUTERS/Stringer (YEMEN - Tags: CRIME LAW ENERGY CIVIL UNREST POLITICS IMAGES OF THE DAY) 

Smoke billows from an oil pipeline blown up in the southern Yemeni province of Shabwa November 2, 2010. Suspected al Qaeda militants blew up the pipeline on Tuesday, local officials said, the same day the country launched a hunt for those responsible for a plot to mail bombs to the United States. The pipeline in the province of Shabwa was operated by a South Korean firm, officials said, but declined to give further details. It was not clear if exports would be affected. REUTERS/Stringer (YEMEN - Tags: CRIME LAW ENERGY CIVIL UNREST POLITICS) 

Smoke billows from an oil pipeline blown up in the southern Yemeni province of Shabwa November 2, 2010. Suspected al Qaeda militants blew up the pipeline on Tuesday, local officials said, the same day the country launched a hunt for those responsible for a plot to mail bombs to the United States. The pipeline in the province of Shabwa was operated by a South Korean firm, officials said, but declined to give further details. It was not clear if exports would be affected. REUTERS/Stringer (YEMEN - Tags: CRIME LAW ENERGY CIVIL UNREST POLITICS IMAGES OF THE DAY) 

A Somali man walks on Bir Ali beach in Yemen October 11, 2006. The man landed on the Yemeni coast after a 36-hour voyage on a small boat from Somalia. Thousands of Somali refugees cross the Gulf of Aden to Yemen every year fleeing war and draught. REUTERS/Khaled Abdullah (YEMEN) 

A Somali man walks on Bir Ali beach in Yemen October 11, 2006. The man landed on the Yemeni coast after a 36-hour voyage on a small boat from Somalia. Thousands of Somali refugees cross the Gulf of Aden to Yemen every year fleeing war and draught. REUTERS/Khaled Abdullah (YEMEN) 

Somali men walk on Bir Ali beach in Yemen October 11, 2006. The men landed on the Yemeni coast after a 36-hour voyage on a small boat from Somalia. Thousands of Somali refugees cross the Gulf of Aden to Yemen every year fleeing war and draught. REUTERS/Khaled Abdullah (YEMEN) 

Somali men walk on Bir Ali beach in Yemen October 11, 2006. The men landed on the Yemeni coast after a 36-hour voyage on a small boat from Somalia. Thousands of Somali refugees cross the Gulf of Aden to Yemen every year fleeing war and draught. REUTERS/Khaled Abdullah (YEMEN) 

Somali men walk on Bir Ali beach in Yemen October 11, 2006. The men landed on the Yemeni coast after a 36-hour voyage on a small boat from Somalia. Thousands of Somali refugees cross the Gulf of Aden to Yemen every year fleeing war and draught. REUTERS/Khaled Abdullah (YEMEN) 

A Somali woman is seen at a temporary refugee shelter one day after landing on the coast in Bir Ali along with 112 Somali refugees in Mayfa'a, Yemen, October 10, 2006. At least 54 people have died making the perilous voyage across the Gulf of Aden between Somalia and Yemen since the beginning of last September, according to the United Nations High Commission for Refugees (UNHCR). REUTERS/Khaled Abdullah (YEMEN)