Fighting broke out north of Yemen's capital and in the center of the country on Sunday, killing more than 20 people, hours before a planned halt to the fighting aimed at facilitating talks to end the year-long war. Yemen's government and its Iran-allied Houthi enemies are supposed to implement the UN-backed 'cessation of hostilities' from midnight before peace negotiations begin in Kuwait on April 18. The United Nations hopes this will lead to a more concrete, formal ceasefire with peace-building steps. The war has killed more than 6,200 people, drawn in rival regional powers Saudi Arabia and Iran and tipped one of the Arab world's poorest countries into a humanitarian crisis.