C AIRO — Iran on Sunday once again denied aiding Yemen's Houthi rebels after the United States launched a wave of airstrikes against them and President Donald Trump warned that Tehran would be held “fully accountable” for their actions.

Under former President Joe Biden, the U.S. and the United Kingdom began a series of airstrikes against the Houthis starting in January 2024. A December report by The International Institute for Strategic Studies said the U.S. and its partners struck the Houthis over 260 times up to that point.

Yemen’s Houthis have proven resilient to a months-long military campaign, spanning the Trump and Biden administrations, to halt the group’s attacks.

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 Iranian-backed rebels, who have targeted Israel and shipping in the Red Sea, said children were among those killed in the strikes ordered by President Trump.