JERUSALEM — Defense Secretary Lloyd Austin said Thursday it’s time to further disable Iran-backed militias that have struck at U.S. forces and ships in the Middle East and the U.S. is preparing to take significant action in response to the deaths of three U.S. service members in Jordan.

For days the U.S. has hinted strikes are imminent. While the threat of retaliation for Sunday’s deaths has driven some militant groups to say they were stopping hostilities, as late as Thursday Yemen’s Houthi rebels were still attacking vessels and fired a ballistic missile at a Liberian-flagged container ship in the Red Sea.

US Response to Attacks

“At this point, it’s time to take away even more capability than we’ve taken in the past,” Austin said Thursday in his first press conference since he was hospitalized on Jan. 1 due to complications from prostate cancer treatment.

Previous U.S. strikes have not deterred the attacks. Since the war between Israel and Hamas broke out in October, Iranian-backed militant groups have struck U.S. bases in Iraq and Syria at least 166 times with rockets, missiles, and one-way attack drones, drawing about a half-dozen U.S. counterstrikes on militant facilities in both countries. The U.S. military also has carried out airstrikes targeting the Iran-backed Houthi rebels in Yemen.

The U.S. has attributed the attack on Tower 22 in Jordan to the Islamic Resistance in Iraq, an umbrella group of Iran-backed militias that includes the militant group Kataib Hezbollah.

Iran’s Involvement

While Iran has denied involvement, Austin said Thursday that “how much Iran knew or didn’t know, we don’t know. But it really doesn’t matter because Iran sponsors these groups.”

Austin said that “without that facilitation, these kinds of things don’t happen.” He said the Pentagon is still looking at the forensics of the drone that struck Tower 22, a secretive base in northeastern Jordan that’s been crucial to the American presence in neighboring Syria.

“I don’t think the adversaries are of a ‘one and done’ mindset. And so they have a lot of capability. I have a lot more,” Austin said. “We’re going to do what’s necessary to protect our troops.”

40 Houthi Attacks in the Red Sea

In the Red Sea, the Houthis have fired on commercial and military ships almost 40 times since November. In the latest attack, they fired a ballistic missile at a Liberian-flagged container ship on Thursday, U.S. defense officials said.

The attack happened west of Hodeida, a port city in Yemen long held by the rebels, said the United Kingdom Maritime Trade Operations, a British military group overseeing Mideast waterways. It said the crew and the vessel were safe and the blast came far off the vessel’s starboard side.

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The U.S. defense officials identified the targeted container ship as the Koi, a Bermuda-owned vessel. Its management could not be immediately reached for comment. The officials spoke on condition of anonymity to discuss intelligence matters. The Houthis did not claim responsibility for the assault.

The Houthis say they are targeting ships over Israel’s offensive in Gaza against Hamas. But they have frequently targeted vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for global trade between Asia, the Mideast and Europe.

The Houthis hit a commercial vessel with a missile on Jan. 26, sparking a fire that burned for hours.

US Military Presence in the Region

The Pentagon has the aircraft carrier Dwight D. Eisenhower in the region, along with at least a half dozen other major U.S. warships, U.S. Air Force fighter jets, and radar aircraft. It has already been regularly using those assets to conduct strikes and defend ships.

Late Wednesday, American F/A-18 fighter jets struck and destroyed 10 Houthi drones that were prepared to launch, as well as a ground control station used by the rebels, the U.S. military said. The U.S. also intercepted a ballistic missile and other drones already in the air during the day.