GENEVA (AP) — The United Nations is set to host peace talks between Yemen's Saudi-backed government and rebels including Iran-aligned Shiite fighters for the first time since 2016, aiming to end a grueling war that has created what the U.N. calls the world's worst humanitarian crisis.

The talks opening Thursday in Geneva mark the possibly best hope to end the war that began spiraling toward catastrophe in March 2015 with the intervention of a Saudi-led, U.S.-backed coalition in support of President Abed Rabbo Mansour Hadi.

The U.N.'s World Food Program says around 18 million people, or two-thirds of Yemen's population, don't know where their next meal will come from and 8 million are "precariously close" to famine.

The new U.N. envoy for Yemen, Martin Griffiths, held a news conference Wednesday.