(Reuters) - The United States carried out an additional strike against Yemen's Houthi forces on Friday, after President Joe Biden's administration vowed to protect shipping in the Red Sea.

The latest strike, which the U.S. said targeted a radar site, came a day after dozens of American and British strikes on the Iran-backed group's facilities.

The guided missile destroyer Carney used Tomahawk missiles in the follow-on strike early on Saturday local time "to degrade the Houthis' ability to attack maritime vessels, including commercial vessels," the U.S. Central Command said in a statement on X, formerly Twitter.

The Houthi movement's television channel Al-Masirah reported that the United States and Britain were targeting the Yemeni capital Sanaa with raids.

Intensifying concerns about a widening regional conflict, U.S. and British warplanes, ships and submarines on Thursday launched missiles against targets across Yemen controlled by the group, which has cast its maritime campaign as support for Palestinians under siege by Israel in Hamas-ruled Gaza.

Even as Houthi leaders swore retaliation, Biden warned on Friday that he could order more strikes if they do not stop their attacks on merchant and military vessels in one of the world's most economically vital waterways.

"We will make sure that we respond to the Houthis if they continue this outrageous behavior," Biden told reporters during a stop in Pennsylvania on Friday.

Witnesses confirmed explosions early on Friday, Yemen time, at military bases near airports in the capital Sanaa and Yemen's third city Taiz, a naval base at Yemen's main Red Sea port Hodeidah and military sites in the coastal Hajjah governorate.

White House spokesperson John Kirby said the initial strikes had targeted the Houthis' ability to store, launch and guide missiles or drones, which the group has used in recent months to threaten Red Sea shipping.

The Pentagon said the U.S.-British assault reduced the Houthis' capacity to launch fresh attacks. The U.S. military said 60 targets in 28 sites were hit.

The Houthis, who control Sanaa and much of the west and north of Yemen, said five fighters were killed, but they vowed to continue their attacks on regional shipping.

The UK Maritime Trade Operations information hub said it had received reports of a missile landing in the sea around 500 meters (1,600 feet) from a ship about 90 nautical miles southeast of the Yemeni port of Aden.

The shipping security firm Ambrey identified it as a Panama-flagged tanker carrying Russian oil.

Drone footage on the Houthis' Al-Masirah TV showed hundreds of thousands of people in Sanaa chanting slogans denouncing Israel and the United States.

"Your strikes on Yemen are terrorism," said Mohammed Ali al-Houthi, a member of the Houthi Supreme Political Council. "The United States is the Devil."

Biden, whose administration removed the Houthis from a State Department list of "foreign terrorist organizations" in 2021, was asked by reporters if he felt the term "terrorist" described the movement now. "I think they are," he said.