By Idrees Ali, Phil Stewart and Mohammed Ghobari
WASHINGTON/ADEN (Reuters) -The Houthi movement 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 United States said hit 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," Nasruldeen Amer, a Houthi spokesperson, told Al Jazeera, adding there had been no injuries nor "material damages".
Mohammed Abdulsalam, another Houthi spokesperson, 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 the U.S.-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 have attacked 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 U.S. Central Command said in a statement on X, formerly Twitter.
In Sanaa, government employee Mohammed Samei said the attacks were an act of "brutal aggression" and marked a new stage of a war Yemen had endured for 10 years.
Hussein Kabsi, a retired government employee, said supporting the Palestinians was a "religious and moral duty".
"Our stance is unwavering, we will (continue) to stand with our brothers in Palestine and Gaza until victory and until all Palestinian land is liberated - not just Gaza," he said.
On Friday, hundreds of thousands of people rallied in Sanaa, chanting slogans denouncing Israel and the United States, footage broadcast by the Houthis' Al-Masirah TV showed
Even as Houthi leaders swore retaliation, U.S. President Joe 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.
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 to threaten shipping. He said Washington had no interest in a war with Yemen.
The Houthis said five fighters were killed in the initial strikes.
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.
SPILLOVER
The Red Sea crisis has added to the spread of conflict through the Middle East since Hamas militants rampaged through southern Israel on Oct. 7, killing 1,200 people and seizing 240 hostages.
Israel has responded by laying waste to large sections of Gaza to try to annihilate Hamas. A total of 23,843 Palestinians have been killed in Israeli strikes on the enclave since Oct. 7, the Gaza health ministry said in a statement on Saturday.
At the United Nations Security Council on Friday, U.S. Ambassador Linda Thomas-Greenfield defended the Yemen strikes, saying they were intended to "to disrupt and degrade the Houthis' ability to continue the reckless attacks against vessels and commercial shipping."
Russia's U.N. Ambassador Vassily Nebenzia said the U.S. and Britain "single-handedly triggered a spillover of the conflict (in Gaza) to the entire region."
The price of Brent crude oil rose more than $2 on Friday on concern that supplies could be disrupted, but later gave up half its gain.
Commercial ship-tracking data showed at least nine oil tankers stopping or diverting from the Red Sea.
The United States and some allies sent a naval task force in December, and recent days saw increasing escalation. On Tuesday, the United States and Britain shot down 21 missiles and drones.
A senior U.S. official accused Tehran of providing the Yemeni group with military capabilities and intelligence to carry out their attacks. Iran condemned the strikes but there has been no sign so far that Iran is seeking direct conflict.
Houthi attacks have forced commercial ships to take a longer, costlier route around Africa, creating concern about a new bout of inflation and supply chain disruption. Container shipping rates for key global routes have soared this week.