The Saudi-led coalition in Yemen said that seven Houthi prisoners will be released, after a Saudi prisoner freed by the group arrived in Riyadh on Tuesday, Saudi state television reported.

Saudi prisoner Mousa Awaji was returned on a Red Cross plane from Sanaa on Tuesday due to illness, the Houthi TV channel al-Masirah said, citing Abdulqadir Murtada, a Houthi official.

The United Nations special envoy to Yemen, Martin Griffiths, welcomed the Saudi prisoner release, tweeting that he hoped to see ¡°more similar humanitarian gestures from the parties,¡± and looked forward to implementation of a prisoner exchange agreement.

Yemen¡¯s warring parties have yet to agree full terms of a prisoner swap, one of the least contentious confidence-building measures agreed at U.N.-sponsored peace talks held in December amid Western pressure to end the conflict.

The United Nations is pushing for the exchange, and the implementation of a cease-fire in the main port city of Hodeida, to pave the way for a second round of discussions to end a war in which tens of thousands of people have been killed in almost four years.