The United Nations human rights chief says a "disproportionate amount" of attacks on civilians in Yemen's conflict appear to be carried out by the Saudi-led and U.S.-supported coalition.

Zeid Raad al-Hussein spoke to a rare public session of the U.N. Security Council on Yemen on Tuesday.

The conflict pits Yemen's internationally recognized government and the coalition against Iran-supported Houthi rebels.

The U.N. this month said the war has killed at least 5,884 people since March, when Saudi Arabia began launching airstrikes targeting the rebels.

U.N.-sponsored peace talks on Yemen collapsed on Sunday in Switzerland but are scheduled to reconvene Jan. 14.

Zeid says a "failed state" in Yemen would almost certainly give space for further growth of extremist groups like the Islamic State organization.