An Arab alliance, fighting Yemen’s Iran-aligned Al Houthis, said Wednesday that its decision to release 200 prisoners linked to the militia group is a humanitarian move.

On Tuesday, the Saudi-led coalition announced the release of the 200 to back efforts to resolve Yemen’s years-long crisis. The alliance also said flights will be operated in cooperation with the World Health Organisation to transport ill people from the Yemeni capital Sana’a which is under Al Houthis’ control.

“This decision is a humanitarian initiative from the alliance for the Yemeni people’s interests,” spokesman for the coalition Col. Turki Al Maliki told Saudi television Al Arabiya.

“The file of the prisoners and detainees is a thorny issue. There are a lot of differences between the legitimate [Yemeni] government and Al Houthis. The UN should make more efforts on this file,” he added.

A UN-brokered deal covering an exchange of prisoners was clinched by the Yemeni government and the militia last December. The pact has since faltered over disagreements between both sides.

Yemen’s conflict erupted in late 2014 when Al Houthis toppled the internationally recognised government and overran parts of the country including Sana’a.

In 2015, the Arab alliance, spearheaded by the UAE and Saudi Arabia, intervened in Yemen in response to a request from the government there.

In recent weeks, there have been media reports about indirect Saudi-Al Houthi talks to peacefully resolve the conflict that has pushed impoverished Yemen to the brink of famine.