Clashes broke out in the Yemeni port city of Hudaydah just minutes after a ceasefire took effect at midnight Tuesday. Yemen's civil war has been raging for almost four years, and Houthi rebels took control of Hudaydah, a port city 90 miles east of the capital Sanaa, in late 2014. Since June, the city has been under assault by the Saudi-led coalition that supports the government. The ceasefire was agreed to last Thursday in Sweden during talks sponsored by the United Nations, but was delayed when fighting broke out on Friday. It's estimated that more than 22 million Yemenis need aid, and Hudaydah is a crucial entrance point for food, medicine, and other supplies.

Scroll for 5 things you
need to know now