Fabrizio Carboni, Regional Director for the Near and Middle East of the International Committee of the Red Cross (ICRC), Abdulkader al-Murtada, Head of the Houthi prisoner exchange committee and Hadi Haig, Head of the Yemeni government delegation, react after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Hadi Haig, Head of the Yemeni government delegation is pictured after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Hadi Haig, Head of the Yemeni government delegation is pictured after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Abdulkader al-Murtada, Head of the Houthi prisoner exchange committee, Hadi Haig, Head of the Yemeni government delegation and Martin Griffiths, United Nations Special Envoy for Yemen pose for a photograph after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Fabrizio Carboni, Regional Director for the Near and Middle East of the International Committee of the Red Cross (ICRC), Abdulkader al-Murtada, Head of the Houthi prisoner exchange committee, Hadi Haig, Head of the Yemeni government delegation and Martin Griffiths, United Nations Special Envoy for Yemen pose for a photograph after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Abdulkader al-Murtada, Head of the Houthi prisoner exchange committee shakes hands with Hadi Haig, Head of the Yemeni government delegation after the closing plenary of the fourth meeting of the Supervisory Committee on the Implementation of the Prisoners' Exchange Agreement in Yemen, in Glion, Switzerland, September 27, 2020. REUTERS/Denis Balibouse

Houthi followers stand by bills of Yemeni currency during a ceremony held by Houthis to collect supplies for their fighters battling government forces in various frontlines, in Sanaa, Yemen September 24, 2020. REUTERS/Khaled Abdullah

Houthi followers stand by bills of Yemeni currency during a ceremony held by Houthis to collect supplies for their fighters battling government forces in various frontlines, in Sanaa, Yemen September 24, 2020. REUTERS/Khaled Abdullah

Houthi followers stand by bills of Yemeni currency during a ceremony held by Houthis to collect supplies for their fighters battling government forces in various frontlines, in Sanaa, Yemen September 24, 2020. REUTERS/Khaled Abdullah TPX IMAGES OF THE DAY

A man, who is not infected by coronavirus, lies on a bed at the emergency ward of a hospital which will be allocated for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

A volunteer for a coronavirus awareness campaign wearing a protective face mask takes notes during a lecture in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 28, 2020. Picture taken March 28, 2020. REUTERS/Khaled Abdullah

Medical staff are pictured at a quarantine center built recently in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. March 29, 2020. REUTERS/Khaled Abdullah

An instructor addresses volunteers for a coronavirus awareness campaign in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 28, 2020. Picture taken March 28, 2020. REUTERS/Khaled Abdullah TPX IMAGES OF THE DAY

Medical staff are pictured at a quarantine center built recently in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

A man wears a protective face mask as he leaves a hospital which is allocated for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

A patient, who is not infected by coronavirus, lies on a bed at the emergency ward of a hospital which will be allocate for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

Volunteers for a coronavirus awareness campaign attend a lecture in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 28, 2020. Picture taken March 28, 2020. REUTERS/Khaled Abdullah

Medical staff are pictured at a quarantine center built recently in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

A medical appliance technician checks an out-of-service ventilator at an ICU unit of a hospital allocated for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

Medical appliance technicians check an out-of-service ventilator at an ICU unit of a hospital allocated for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

Medical staff are pictured at a quarantine center built recently in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020.Picture taken March 29, 2020. REUTERS/Khaled Abdullah

People leave a hospital allocated for coronavirus patients in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 29, 2020. Picture taken March 29, 2020. REUTERS/Khaled Abdullah

A volunteer for a coronavirus awareness campaign wearing a protective face mask attends a lecture in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 28, 2020. Picture taken March 28, 2020. REUTERS/Khaled Abdullah

Volunteers for a coronavirus awareness campaign wearing protective face masks attend lecture in preparation for any possible spread of the coronavirus disease (COVID-19), in Sanaa, Yemen March 28, 2020. Picture taken March 28, 2020. REUTERS/Khaled Abdullah

A Yemeni soldier looks at his mobile phone during a rally against the U.S. President Donald Trump's Middle East peace plan, in Sanaa, Yemen January 31, 2020. REUTERS/Mohamed al-Sayaghi

Bundles of Yemeni Riyal banknotes are pictured at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Employees count bundles of newly issued Yemeni Riyal bank notes at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Employees count bundles of Yemeni Riyal at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

An employee checks a bundle of Yemeni Riyal at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Bundles of Yemeni Riyal banknotes are pictured at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

An employee takes bundles of Yemeni Riyal at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Employees count bundles of Yemeni Riyal at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Employees count bundles of newly issued Yemeni Riyal bank notes at the Central Bank of Yemen in Sanaa January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Bundles of newly issued Yemeni Riyal bank notes are pictured at the Central Bank of Yemen in Sanaa, Yemen January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

An employee counts newly issued bundles of Yemeni Riyal at the Central Bank of Yemen in Sanaa, Yemen January 7, 2020. Picture taken January 7, 2020. REUTERS/Khaled Abdullah

Army officers and soldiers who have defected from the ranks of Yemeni government forces shout Houthi slogans during a ceremony held by the Houthis in Sanaa, Yemen December 29, 2019. REUTERS/Khaled Abdullah

Soldiers who have defected from the ranks of Yemeni government forces salute for the national anthem during a ceremony held by the Houthis in Sanaa, Yemen December 29, 2019. REUTERS/Khaled Abdullah

Southern Yemeni separatist security members patrol a road during a campaign to seize unlicensed motorcycles in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

A southern Yemeni separatist security member checks a seized unlicensed motorcycle in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

A southern Yemeni separatist security member stands by seized unlicensed motorcycles in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist security members check seized unlicensed motorcycles in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist security members patrol a street during a campaign to seize unlicensed motorcycles in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist security members patrol a street during a campaign to seize unlicensed motorcycles in Aden, Yemen December 10, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist fighters stand guard outside the headquarters of the Southern Transitional Council in Aden, Yemen November 5, 2019. REUTERS/Fawaz Salman

Yemeni people visit Dar al-Hajar tourist site in the outskirts of Sanaa, Yemen September 26, 2019. Picture taken September 26, 2019. REUTERS/Mohamed al-Sayaghi ?

Armed Houthi followers stand guard at the site of a rally to mark the 5th anniversary of the Houthi movement's takeover of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

A Houthi follower shouts slogans as he attends a rally to mark the 5th anniversary of the Houthi movement's take-over of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

Houthi followers rally to mark the 5th anniversary of their movement's takeover of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

Houthi followers rally to mark the 5th anniversary of their movement's takeover of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

Houthi followers rally to mark the 5th anniversary of their movement's takeover of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

Houthi followers rally to mark the 5th anniversary of their movement's takeover of the Yemeni capital Sanaa, in Sanaa, Yemen September 21, 2019. REUTERS/Khaled Abdullah

Yemeni coast guards prepare to escort a tug boat ferrying members of a Houthi delegation to attend a meeting of a committee overseeing a U.N.-led peace deal that will be held on board a U.N.-chartered ship off Yemen's port city of Hodeidah September 8, 2019. REUTERS/Abduljabbar Zeyad

A Yemeni coast guard boat escorts a tugboat ferrying members of a Houthi delegation to attend a meeting of a committee overseeing a U.N.-led peace deal that will be held on board a U.N.-chartered ship off Yemen's port city of Hodeidah September 8, 2019. REUTERS/Abduljabbar Zeyad

Yemeni southern separatist leaders sit during a rally in support to the United Arab Emirates amid a standoff with the Saudi-backed government, in the port city of Aden, Yemen September 5, 2019. REUTERS/Fawaz Salman

Yemeni southern separatist leaders stand during a rally in support to the United Arab Emirates amid a standoff with the Saudi-backed government, in the port city of Aden, Yemen September 5, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist men guard a checkpoint in Aden, Yemen August 31, 2019. REUTERS/Fawaz Salman

Southern Yemeni separatist men are seen at a checkpoint in Aden, Yemen August 31, 2019. REUTERS/Fawaz Salman

A southern Yemeni separatist security member checks a car at a checkpoint in Aden, Yemen August 31, 2019. REUTERS/Fawaz Salman