Aid group urges pressure in Yemen to keep cease-fire A humanitarian group is warning that a cease-fire in Yemen's port city of Hodeida is on the verge of collapse, urging the international community _ especially the U.S. and Britain _ to step up pressure on the warring parties to stick to their commitments

CAIRO -- A humanitarian group warned Monday that a cease-fire in Yemen's port city of Hodeida is on the verge of collapse, urging the international community — especially the U.S. and Britain — to step up pressure on the warring parties to stick to their commitments.

Clashes have erupted since last week between the Houthi rebels, who control the city, and pro-government forces backed by a Saudi-led coalition, threatening to unravel agreements signed in Sweden last month, the U.S.-based International Rescue Committee said in a statement.

"In recent days, with clashes erupting inside Hodeida, and both parties accusing each other of violations, the agreement is increasingly in peril," Frank McManus of the group said. "Fighting in the city and disruptions to imports through the port could propel the country into a full-fledge famine."

U.N. envoy Martin Griffiths arrived in Hodeida later in the day and met with both sides in hopes of making some progress in implementing the cease-fire and an agreed-upon prisoner exchange that has yet to take place. Griffiths urged all sides to withdraw from the port city as agreed.

Separately, the rebels released a Saudi prisoner who had taken ill in a sign of goodwill, their media reported.

Yemen was plunged into civil war in 2014 when the rebels captured the capital, Sanaa. A coalition led by Saudi Arabia entered the war on the side of the government in March 2015. The war has killed tens of thousands of people and has generated the world's worst humanitarian crisis.