Updated

The U.N. secretary-general is joining top officials from dozens of countries at a pledging conference for war-battered Yemen, a relatively overlooked conflict that has killed thousands and created the world's biggest humanitarian crisis.

Sweden and Switzerland joined the United Nations and Secretary-General Antonio Guterres in hosting the day-long event aimed at raising awareness and mobilizing resources amid a deteriorating situation in the poor Arabian Peninsula nation.

Tuesday's gathering will drum up funds toward the U.N.'s $2.96 billion appeal to provide assistance and protection to people in Yemen.

A Saudi-led coalition has been at war with Iran-allied Shiite rebels for more than three years in a conflict that has killed more than 10,000 people and left 22.2 million people in need of humanitarian aid.