Freed Houthi prisoners pray as they arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. Planes carrying prisoners to be exchanged by Yemen's warring parties took off on Friday on the second day of an operation to return about 1,000 men home and help build momentum for a new push to end a catastrophic war. REUTERS/Khaled Abdullah

Freed Houthi prisoners arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. A Saudi-led military coalition, which supports the internationally recognised Yemeni government, and Yemen's Iran-aligned Houthi movement agreed last month in Switzerland to exchange 1,081 prisoners, including 15 Saudis, in the largest swap of its kind in the five-year-old conflict. REUTERS/Khaled Abdullah

Freed Houthi prisoners shout slogans as they arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. REUTERS/Khaled Abdullah

Freed Houthi prisoners arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. REUTERS/Khaled Abdullah

Freed Houthi prisoners shout slogans as they arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. REUTERS/Khaled Abdullah

Freed Houthi prisoners shout slogans as they arrive after their release in a prisoner swap, in Sanaa airport, Yemen October 15, 2020. REUTERS/Khaled Abdullah