The Saudi-led coalition engaged in Yemen said on Friday it had started transporting released prisoners to Yemen in coordination with the International Committee of the Red Cross (ICRC) under a humanitarian initiative to support a U.N.-brokered truce.

The coalition said last month it would release 163 prisoners from Yemen’s Iran-aligned Houthi group who fought against Saudi Arabia, but a Houthi official later said the list included individuals who did not belong to the movement.

The ICRC spokesperson in Yemen, Bashir Omar, told Reuters that 108 freed detainees would be flown from Saudi Arabia to the southern port city of Aden, where Yemen’s Saudi-backed government is based, and nine to the Houthi-held capital Sanaa.

The coalition said two flights had left for Yemen and a third was also due. It said it was handing over “foreign fighters” to their embassies, Saudi state news agency SPA reported, without specifying nationalities or numbers.

A Yemeni government official told Reuters that the Houthis only agreed to take nine prisoners so the rest were flown to Aden. Earlier this month, the head of the Houthis’ prisoner affairs committee said the list of detainees included people “unknown to us and who are not among our prisoners”.

The coalition intervened in Yemen in March 2015 against the Houthis after the movement ousted the internationally recognised government from Sanaa in late 2014.

The warring parties agreed on a two-month truce that began on April 2 in the first major breakthrough in years under U.N.-led efforts to end the war that has killed tens of thousands and caused a dire humanitarian crisis.

They had also been discussing a potential prisoner swap under the auspices of the United Nations involving 1,400 Houthi prisoners and 823 coalition prisoners, including 16 Saudis.

The last major prisoner exchange, involving around 1,000 detainees, took place in 2020.