U.S. Central Command continued strikes against the group Sunday and Monday, launching a campaign that may last weeks, officials said.

Yemen's Houthi rebels say there have been fresh US strikes against them, with the number of dead rising to 53, including five children. Targets in the Al Jaouf and Hudaydah areas were hit early on Monday, according to the rebel group, while the US Central Command said its forces had continued operations.

The comments by Trump on his Truth Social website escalate his administration's new campaign of airstrikes targeting the rebels.

President Donald Trump announced he ordered the U.S. military to launch "decisive and powerful military action" against the Houthis in Yemen.

Oil prices rose slightly on Monday after the United States vowed to keep attacking Yemen's Houthis until the Iran-aligned group ends its assaults on shipping, while Chinese economic data buoyed hopes for higher demand.

Oil futures climbed on Monday, finding support after the U.S. over the weekend launched U.S. strikes on Houthi rebels in Yemen, raising the risk of disruptions to oil flow in the region.

Oil prices were up nearly 1 per cent on Monday after the US bombed Yemen's Houthis for a second night, warning of an “unrelenting” attack on the militant group, and as China announced stimulus plans to boost its tepid economy.