US retaliatory airstrikes updates: White House vows to take 'more action'

U.S. Central Command forces conducted what CENTCOM said was a "strike in self-defense against a Houthi land attack cruise missile," earlier on Sunday.

CENTCOM confirmed the incident -- which it said was due to an "imminent threat" -- happened at 10:30 a.m. local time. U.S. forces hit four anti-ship cruise missiles in Houthi-controlled areas of Yemen, which it says were "prepared to launch against ships in the Red Sea."

CENTCOM said the threat was to U.S. Navy ships and merchant vessels in the area.

"These actions will protect freedom of navigation and make international waters safer and more secure for U.S. Navy vessels and merchant vessels," CENTCOM said in a release Sunday night.

-ABC News' Nathan Luna

The U.S. will take "more action" against Iran-backed militants in response to the deadly drone attack in Jordan last week, the White House's national security adviser said in an interview on Sunday.

"This was the beginning of our response, there will be more steps," Jake Sullivan told ABC News "This Week" anchor George Stephanopoulos. "Some of those steps will be seen, some may not be seen. But there will be more action taken to respond to the the tragic death of the three brave U.S. service members."

The U.S. has blamed Iran-backed fighters for the attack on Tower 22 in Jordan on Jan. 28.

Iran has denied involvement. Pressed by Stephanopoulos whether additional strikes could escalation tension with Iran, Sullivan said it's something the U.S. is prepared for.

"This is something that we have to look at as a threat," he said. "We have to prepare for every contingency, and we are prepared for that contingency. And I would just say, from the perspective of Tehran, if they chose to respond directly to the United States, they would be met with a swift and forceful response from us."

-ABC News' Fritz Farrow

Early Sunday morning, the United States conducted a strike "in self-defense against a Houthi anti-ship cruise missile prepared to launch against ships in the Red Sea," a statement from the U.S. Central Command forces said.

Around 4 a.m. locally, U.S. forces identified a cruise missile in Houthi-controlled areas of Yemen and determined it presented an imminent threat to U.S. Navy ships and merchant vessels in the region, according to CENTCOM.

According to the release, "This action will protect freedom of navigation and make international waters safer and more secure for U.S. Navy vessels and merchant vessels."

The round of airstrikes launched by the U.S. and U.K. on Saturday “further degraded the Houthis’ capability to continue their illegal and reckless attacks" against U.S. ships and international commercial vessels, according to a senior U.S. administration official.

"The U.S. does not want escalation, and these strikes are directly in response to the actions by the Iranian-backed Houthis," the senior administration official said. "They are unrelated to the action the United States took on Friday in response to the continued attacks on our troops and facilities in Iraq and Syria."

The official emphasizes that the U.S. has “rallied a global coalition” to condemn and hold the Houthis accountable, adding that this is the third round of strikes as part of the coalition that includes the U.S., UK, Australia, Bahrain, Canada, the Netherlands, and now also Denmark and New Zealand.

-ABC News' Selina Wang