BEIRUT (AP) — The United States (US) military said Sunday that its forces opened fire on Houthi rebels after they attacked a cargo ship in the Red Sea, killing several of them in an escalation of the maritime conflict linked to the war in Gaza. “We’re going to act in self-defence going forward,” a White House official said.

In a series of statements, the US Central Command said the crew of the USS Gravely destroyer first shot down two anti-ship ballistic missiles fired at the Singapore-flagged Maersk Hangzhou late Saturday, after the vessel reported getting hit by a missile earlier that evening as it sailed through the Southern Red Sea.

Four small boats then attacked the same cargo ship with small arms fire early Sunday and rebels tried to board the vessel, the US Navy said.

Next, the USS Gravely and helicopters from the USS Dwight D Eisenhower aircraft carrier responded to the Maersk Hangzhou’s distress call and issued verbal warnings to the attackers, who responded by firing on the helicopters.

“The US Navy helicopters returned fire in self-defence,” sinking three of the four boats and killing the people on board while the fourth boat fled the area, the US Central Command said. No harm to US personnel or equipment, or casualties from the cargo ship, were reported.

The Houthis acknowledged that 10 of their fighters were killed in the confrontation and warned of consequences.

In Washington, a spokesman for the White House National Security Council sidestepped a question about the possibility of a preemptive strike against the Houthis to safeguard commercial shipping in the vital waterway.

“I won’t say what’s on or off the table right now,” John Kirby told ABC’s “Good Morning America,” adding, “We’re going to do what we have to do to protect shipping.” He said the United States has “significant national security interests in the region” and “we’re going to put the kind of forces we need in the region to protect those interests and we’re going to act in self-defence going forward.”

He said the US has made it clear to the Houthis that “we take these threats seriously and we’re going to make the right decisions going forward.″

The events surrounding the Maersk Hangzhou represented the 23rd illegal attack by the Houthis on international shipping since November 19, the Central Command said. It was the first time the US Navy said its personnel had killed Houthi fighters since the Red Sea attacks started.

For over a month, Iran-backed Houthis have claimed attacks on ships in the Red Sea that they say are either linked to Israel or heading to Israeli ports. They say their attacks aim to end the Israeli air-and-ground offensive in the Gaza Strip that was triggered by the Palestinian militant group Hamas’ October 7 attack in southern Israel.

However, the links to the ships targeted in the rebel assaults have grown more tenuous as the attacks continue.

The chairman of the House Intelligence Committee called on President Joe Biden “to look at what actions need to be taken in Yemen to be able to prevent the Houthis to continue to put commercial and military vessels at risk.”

Noting Iran’s support for Hamas, Hezbollah and the Houthis, Rep. Mike Turner, R-Ohio, told ABC’s “This Week” that the Biden administration should be more aggressive “in responding to escalation by Iran.’’

The Denmark-based shipping giant Maersk, owner of Maersk Hangzhou, said Sunday it would suspend shipping through the Red Sea again after the two attacks on its freighter.

“In light of the (most recent) incident — and to give time to investigate the details of the incident and assess the security situation further — it has been decided that all transits through the area will be postponed for the next 48 hours,” Maersk was quoted as saying by the Danish public broadcaster DR.

On Saturday, the top commander of US naval forces in the Middle East said Houthi rebels have shown no signs of ending their “reckless” attacks on commercial ships in the Red Sea even as more nations join the international maritime mission to protect vessels in the vital waterway and trade traffic begins to pick up.

Earlier this month, Washington announced the establishment of a new international coalition to protect vessels travelling through the waterway. The United Kingdom, Bahrain, Canada, France, Italy, the Netherlands, Norway, Seychelles and Spain are also part of the new maritime security mission.

Since the Pentagon announced Operation Prosperity Guardian to counter the attacks just over 10 days ago, 1,200 merchant ships have travelled through the Red Sea region, and none had been hit by drone or missile strikes, Vice Adm. Brad Cooper told The Associated Press in an interview on Saturday.