The Houthi movement has threatened a "strong and effective response" after the United States carried out another strike in Yemen overnight, further ratcheting up tensions as Washington vows to protect shipping from attacks by the Iran-aligned group.
The strikes have added to concerns about the escalation of the conflict that has spread through the region since the Palestinian militant group Hamas and Israel went to war, with Iran's allies also entering the fray from Lebanon, Syria and Iraq.
The latest strike, which the US said targeted a radar site, came a day after dozens of American and British strikes on Houthi facilities in Yemen.
"This new strike will have a firm, strong and effective response," Houthi spokesman Nasruldeen Amer told Al Jazeera, adding there had been no injuries nor "material damages".
Mohammed Abdulsalam, another Houthi spokesman, told Reuters the strikes, including the one overnight that hit a military base in Sanaa, had no significant impact on the group's ability to prevent Israel-affiliated vessels from passing through the Red Sea and the Arabian Sea.
The Pentagon said on Friday that the US-British strikes had "good effects".
The Houthis say their maritime campaign aims to support Palestinians under Israeli siege and attack in Gaza, which is ruled by the Iran-backed Hamas.
Many of the vessels they targeted had no known connection to Israel.
The group, which controls Sanaa and much of the west and north of Yemen, has also fired drones and missiles up the Red Sea at Israel itself.
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 US Central Command said in a statement on X.
Even as Houthi leaders swore retaliation, Biden warned earlier on Friday he could order more strikes if they did 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 behaviour," Biden told reporters in Pennsylvania.
White House spokesman John Kirby said the strikes had targeted the Houthis' ability to store, launch and guide missiles or drones.
The Houthis said five fighters were killed in the initial strikes.
Drone footage on the Houthis' Al-Masirah TV showed hundreds of thousands of people in Sanaa chanting slogans denouncing Israel and the US on Friday.
Biden, whose administration removed the Houthis from a State Department list of "foreign terrorist organisations" in 2021, was asked by reporters if the term "terrorist" described the movement now.
"I think they are," he said.
The Red Sea crisis has added to the spread of conflict through the Middle East since Hamas militants rampaged through southern Israel on October 7, killing 1200 people and seizing 240 hostages
Israel has responded by laying waste to large sections of Gaza to eradicate Hamas.
A total of 23,843 Palestinians have been killed in Israeli strikes on the enclave since October 7, the Gaza health ministry said in a statement on Saturday.
Russia's UN Ambassador Vassily Nebenzia said the US and Britain had "single-handedly triggered a spillover of the conflict (in Gaza) to the entire region".
Commercial ship-tracking data showed at least nine oil tankers stopping or diverting from the Red Sea.
The US and some allies sent a naval task force in December, with escalation increasing recently.
The strikes inside Yemen have not been backed by all major US allies.
The Netherlands, Australia, Canada and Bahrain provided logistical and intelligence support, while Germany, Denmark, New Zealand and South Korea signed a joint statement defending the attacks and warning of further action.
But Italy, Spain and France chose not to sign or participate, fearing a wider escalation.
