“These targeted strikes are a clear message that the United States and our partners will not tolerate attacks on our personnel or allow hostile actors to imperil freedom of navigation in one of the world’s most critical commercial routes,” President Joe Biden said in a statement.

American and British forces struck radar installations and storage and launch sites for drones, cruise missiles and ballistic missiles, according to US officials, who asked not to be identified discussing operational details. The attacks came from Air Force jets and fighter jets based on the USS Eisenhower aircraft carrier, as well as Tomahawk missiles launched from a submarine and surface ships.

The strikes were intended to cripple the militant group’s ability to attack commercial vessels following Houthi barrages of drones and missiles fired into a vital trade waterway. Biden said Australia, Bahrain, Canada and the Netherlands provided what a US official called non-operational support.

Thursday night’s action marks a significant escalation in the weeks since Hamas militants attacked Israel on Oct. 7 and Israeli forces responded with a devastating air and ground campaign in the Gaza Strip. The Houthis began their harassment of commercial vessels soon after and have vowed not to let up until Israel ends its assault on Gaza.

The strikes took place hours after Secretary of State Antony Blinken ended a trip through the Middle East that was aimed in part at getting support for more aggressive action toward the Houthis, as he insisted “there will have to be consequences” if the attacks at sea persisted. Earlier Thursday, the Houthis fired a ballistic missile in the Gulf of Aden, in what US officials said was the 27th attack on commercial shipping by the group since Nov. 19.

Global crude oil benchmark Brent moved higher by almost 2% to match the move in West Texas Intermediate following the strikes in Yemen.

Heavy explosions were reported in the Yemeni capital of Sana’a and the port city of Al Hudaydah. The target sites were assessed as having no civilians nearby, one of the officials said, adding that early indications suggested the impact on the Houthis’ ability to launch future attacks was significant.

Who Are the Houthis Being Hit With US, UK Airstrikes: QuickTake

The strikes embroil the US in yet another fight with an Iranian proxy, after US forces launched attacks in Syria and Iraq in recent weeks in a bid to quash Iranian-supported militias that had launched drones and missiles at US bases — so far without major casualties. The Iran-backed Palestinian Islamic Jihad Movement condemned the strikes and urged “the people of the Arab and Islamic nation to take action.”

Deterring the Houthis for good won’t be easy. The group, which took control of the Yemeni capital Sana’a in 2014, has successfully withstood a Saudi Arabia-led military campaign to oust it that began a year later, and remains firmly entrenched. Previous efforts to deter attacks have also failed. Late last month, the US spearheaded the creation of a maritime task force — dubbed Operation Prosperity Guardian — whose goal was to provide security for vessels transiting the Red Sea.

In a televised speech earlier Thursday, Houthi leader Abdul Malik Al-Houthi vowed a “big” response to the US and its allies if they proceeded with military action against his group.

“We’ll confront the American aggression,” he said. “Any American attack won’t go unpunished.”

The Houthi action in the Red Sea had prompted many commercial shippers to direct their vessels around the southern tip of Africa rather than risk more Houthi attacks. That’s increased shipping times and threatened to snarl supply chains. Biden said in his statement that more than 2,000 ships had been forced to divert thousands of miles to avoid the Red Sea.

But the extensive airstrikes are also a gamble for the US, which has repeatedly said a top priority amid the Israel-Hamas fighting is to keep the conflict from spreading into a bigger regional war. The US and its allies went ahead despite concerns from Qatar, Saudi Arabia and other nations in the region that strikes would only further inflame tensions.

After the strikes occurred, Saudi Arabia called for restraint and avoiding escalation “in light of the events the region is witnessing,” according to a statement carried by the official SPA news agency.