Five international charities on Monday urged the United States to halt all military support for a Saudi-led coalition fighting Yemen's Shia rebels, saying this will save millions of lives.

A joint statement by the International Rescue Committee, Oxfam America, CARE US, Save the Children, and the Norwegian Refugee Council said that 14 million people are at risk of starving to death in Yemen if the parties to the conflict don't change course immediately.

The warring sides have undermined Yemen's economy with policies and practices that have caused rampant inflation while the value of currency plummets, it added.

"Starvation must not be used as a weapon of war against Yemeni civilians," the statement said.

The charities called the US to back up its recent call for a cessation of hostilities in Yemen with genuine diplomatic pressure, mainly Saudi Arabia and the United Arab Emirates.

International outrage over the killing of journalist Jamal Khashoggi by Saudi agents in October in Turkey has also focused attention on Yemen's civil war, prompting the US to scale back its support for the coalition and call for a cease-fire by the end of this month.

In March 2015, the US-backed, Saudi-led coalition unleashed a full-scale military campaign against Iran-allied Houthi rebels who had captured most of Yemen including the capital, Sanaa, a few months earlier.

Tens of thousands of people have been killed in the war.

If it doesn't cease its military support for the coalition, "the United States, too, will bear responsibility for what may be the largest famine in decades," the charities said.