Aid groups warned of the plight of civilians in Yemen's contested Hodeida where casualties are mounting as a Saudi-led coalition is fighting to take the port city from the country's Shiite rebels. Separate from the warning, a collection of aid groups, including CARE and 34 others, issued a statement yesterday, calling for an immediate cease-fire in Yemen.

Amnesty International warned late Wednesday that rebels have taken up positions on a Hodeida hospital rooftop, raising concerns they are using the hospital's patients as human shields to ward off coalition airstrikes. Doctors Without Borders, meanwhile, said it was treating two dozen wounded from the latest offensive.

Amnesty urged the warring sides to protect civilians. It said that the coalition, which relies heavily on air power, has killed scores of civilians in recent airstrikes, and rebels are responding with mortars in residential neighborhoods that cause indiscriminate casualties. "The presence of Houthi fighters on the hospital's roof violates international humanitarian law," said Amnesty's Samah Hadid, adding that "this violation does not make the hospital and the patients and medical staff lawful targets" for the coalition.

Yemen has been wracked by conflict since 2014, when Shiite Houthi rebels overran much of the country. Saudi Crown Prince Mohammed bin Salman, the former defense minister, and Saudi Arabia's allies launched Operation Decisive Storm in March 2015. Riyadh has accused the Houthi rebel group of serving as a proxy force for Iran, Saudi Arabia's arch foe in the region.

Civilians have borne the brunt of the conflict, which has killed over 10,000 people and sparked the world's worst humanitarian crisis. In September, the Saudi-led coalition admitted that mistakes were made in an August airstrike that killed 40 children, an event considered an apparent war crime by the U.N. human rights body. Saudi Arabia's alleged human rights violations are not limited to that country but have expanded beyond its borders, since there is an endless war in Yemen.

The U.S. has made a call to end the war, but there was no reference to the future of its arms sales to Saudi Arabia. The U.N. has made no progress in attempts to get the warring sides to negotiate a peaceful resolution to the conflict.