Former U.S. President Donald Trump has declared that he ordered a “decisive” military operation against Houthi rebels in Yemen, intensifying efforts against the Iran-backed group responsible for attacks on Red Sea shipping lanes.

U.S. airstrikes on Saturday resulted in at least 23 deaths and over 20 injuries, according to the Houthi-controlled health ministry.

In a post on Truth Social, Trump vowed to unleash "overwhelming lethal force" against the Houthis “until our objective is achieved,” condemning their "campaign of piracy, violence, and terrorism" against American and allied vessels, aircraft, and drones.

He stated that U.S. forces were conducting air raids on Houthi bases, leadership, and missile sites to safeguard American commercial and naval operations and restore freedom of navigation.

“No terrorist force will prevent American ships from freely sailing the world’s waterways,” Trump wrote.

Trump also issued a warning to Iran, the Houthis’ primary supporter, demanding an end to its backing of the group and cautioning that any threat against the U.S. or its leadership would result in severe consequences.

The Houthi-run health ministry reported casualties in the capital, Sanaa, and the northern province of Saada, where airstrikes hit a power station, causing a citywide blackout.

Anees Alasbahi, a spokesperson for the Houthi-run health ministry, condemned the strikes as “criminal escalation” and vowed that they would only strengthen Yemeni resolve to support Gaza and regional resistance efforts.

According to U.S. officials, Trump had approved plans for the strikes weeks earlier, with Saturday’s attacks marking the beginning of a sustained military campaign.

Further actions will be determined based on battle damage assessments, with additional strikes expected in the coming weeks. Officials noted that intelligence collection for broader targeting had been completed.

Secretary of State Marco Rubio emphasized to Russian Foreign Minister Sergei Lavrov that continued Houthi aggression against U.S. and commercial vessels would not be tolerated.

The Biden administration had previously attempted targeted strikes on Houthi infrastructure in late 2023, but the group continued attacks, citing support for Palestinians in Gaza.

The Houthis had previously stated they would halt their Red Sea attacks if a ceasefire was upheld between Israel and Hamas, linking their actions to the humanitarian crisis in Gaza.

A U.S. official that the current campaign is expected to last for days or weeks, though there are no plans for a ground invasion.

Earlier this year, Trump re-designated the Houthis as a "foreign terrorist organization." He criticized the Biden administration’s response as weak, arguing that it emboldened the Houthis to escalate their attacks.

“To all Houthi terrorists, YOUR TIME IS UP, AND YOUR ATTACKS MUST STOP, STARTING TODAY. IF THEY DON’T, HELL WILL RAIN DOWN UPON YOU LIKE NOTHING YOU HAVE EVER SEEN BEFORE!” Trump declared.