President Donald Trump said he ordered a series of airstrikes on Yemen’s capital, Sanaa, on Saturday, promising to use “overwhelming lethal force” until Iranian-backed Houthi rebels cease their attacks on shipping along a vital maritime corridor.

“Our brave Warfighters are right now carrying out aerial attacks on the terrorists’ bases, leaders, and missile defenses to protect American shipping, air, and naval assets, and to restore Navigational Freedom,” Trump said in a social media post. “No terrorist force will stop American commercial and naval vessels from freely sailing the Waterways of the World.”

He also warned Iran to stop supporting the rebel group, promising to hold the country “fully accountable” for the actions of its proxy. It comes two weeks after the U.S leader sent a letter to Iranian leaders offering a path to restarting bilateral talks between the two countries on Iran’s advancing nuclear weapons program that Trump has said he will not allow to become operational.

The Houthis reported a series of explosions in their territory Saturday evening. Images circulating online show plumes of black smoke over the area of the Sanaa airport complex, which includes a sprawling military facility.

The airstrikes come a few days after the Houthis said they would resume attacks on Israeli vessels sailing in waters off Yemen in response to Israel’s blockade on Gaza. There have been no Houthi attacks reported since then.

Earlier this month, Israel halted all aid coming into Gaza and warned of “additional consequences” for Hamas if their fragile ceasefire in the war isn’t extended as negotiations continue over starting a second phase.

The Houthis had described their warning as taking hold in the Red Sea, the Gulf of en, the Bab el-Mandeb Strait and the Arabian Sea.

The Houthis targeted over 100 merchant vessels with missiles and drones, sinking two vessels and killing four sailors, during their campaign targeting military and civilian ships between the start of the war between Israel and Hamas in late 2023 and January of this year, when a tenuous ceasefire in Gaza took effect.

The attacks greatly raised the Houthis’ profile as they faced economic problems and launched a crackdown targeting any dissent and aid workers at home amid Yemen’s decade-long stalemated war that’s torn apart the Arab world’s poorest nation.

The United States, Israel and Britain have previously hit Houthi-held areas in Yemen. Israel’s military declined to comment.

The Houthi media office said the U.S. strikes hit “a residential neighborhood” in Sanaa’s northern district of Shouab. Sanaa residents said at least four airstrikes rocked the Eastern Geraf neighborhood in Shouab district, terrifying women and children in the area.

“The explosions were very strong,” said Abdallah al-Alffi. “It was like an earthquake.”

The Saturday operation against the Houthis was conducted solely by the U.S., according to a U.S. official. It was the first strike on the Yemen-based Houthis under the second Trump administration, and it comes after a period of relative quiet in the region.

Such broad-based and pre-planned missile strikes against the Houthis were done multiple times by the Biden administration in response to frequent attacks by the Houthis against commercial and military vessels in the region.

The USS Harry S. Truman carrier strike group, which includes the carrier, three Navy destroyers and one cruiser, are in the Red Sea and were part of the mission. The USS Georgia cruise missile submarine has also been operating in the region.

Trump announced the strikes as he spent the day at his Trump International Golf Club in West Palm Beach, Florida.

“These relentless assaults have cost the U.S. and World Economy many BILLIONS of Dollars while, at the same time, putting innocent lives at risk,” Trump said.