Fears of a wider conflict have gripped the Middle East after U.S. and British forces carried out airstrikes on Yemen's Houthi rebels over their attacks on Red Sea shipping.

The pre-dawn airstrikes fueled fears of regional conflict, where violence involving Tehran-backed groups in Yemen as well as Lebanon, Iraq and Syria has surged since Israel's war on Gaza began on Oct. 7.

Iran "strongly condemned" the strikes, which the United States, Britain and eight other allies said aimed to "de-escalate tensions."

China said it was "concerned about the escalation of tensions in the Red Sea," and news of the strikes sent oil prices up more than 2%.

The Houthis have carried out a growing number of attacks on what they deem to be Israeli-linked shipping in the key international trade route since the Oct. 7 Hamas attack sparked Israel's war, which has devastated Gaza Strip.

The rebels have controlled a major part of Yemen since a civil war erupted there in 2014 and are part of a regional Iran-backed "axis of resistance" against Israel and its allies.

Friday's strikes targeted an airbase, airports and a military camp, the Houthis' Al-Masirah TV station said, with AFP correspondents and witnesses reporting they could hear heavy strikes in Hodeida and Sanaa.

"Our country was subjected to a massive aggressive attack by American and British ships, submarines and warplanes," said Hussein al-Ezzi, the rebels' deputy foreign minister.

"America and Britain will have to prepare to pay a heavy price and bear all the dire consequences of this blatant aggression," he added according to official Houthi media.

U.S. President Joe Biden called the strikes a "defensive action" after the Red Sea attacks and said he "will not hesitate" to order further military action if needed.

With fighter jets and Tomahawk missiles, 60 targets at 16 Houthi locations were hit by more than 100 precision-guided munitions, U.S. Central Command said in a statement.

Unverified images on social media, some of them purportedly of Al-Dailami airbase north of the rebel-held capital Sanaa, showed explosions lighting up the sky as loud bangs and the roar of planes sounded.

Houthi military spokesperson Yahya Saree said at least five people had been killed.

'Repeated warnings'

Nasser Kanani, spokesman for Iran's foreign ministry, said that the Western strikes "will have no result other than fueling insecurity and instability in the region," while "diverting the world's attention" from Gaza.

In a statement, Biden called the strikes a success and said he ordered them "against a number of targets in Yemen used by Houthi rebels to endanger freedom of navigation in one of the world's most vital waterways."

Biden called the strikes a "direct response" to the "unprecedented" attacks by the Houthis which included "the use of anti-ship ballistic missiles for the first time in history."

Blaming the Houthis for ignoring "repeated warnings," British Prime Minister Rishi Sunak said in a statement the strikes were "necessary and proportionate."

Britain's Defense Ministry released footage of Royal Air Force jets returning to their Cyprus base after the mission, and U.S. CENTCOM video showed warplanes apparently taking off from a sea-based carrier.

U.S. Defense Secretary Lloyd Austin said the strikes "targeted sites associated with the Houthis' unmanned aerial vehicle, ballistic and cruise missile, and coastal radar and air surveillance capabilities."

A joint statement by the United States, Britain, Australia, Bahrain, Canada, Denmark, Germany, the Netherlands, New Zealand and South Korea said the "aim remains to de-escalate tensions and restore stability in the Red Sea."

The Houthis said they will not be deterred.

"We affirm that there is absolutely no justification for this aggression against Yemen, as there was no threat to international navigation in the Red and Arabian Seas," Houthi spokesperson Mohammed Abdulsalam posted on X, formerly Twitter.

He said there was no threat to any vessels apart from "Israeli ships or those heading to the ports of occupied Palestine".

Prior to Friday's strikes, Gerald Feierstein, a former U.S. ambassador to Yemen, said bombing the Houthis would be "counter-productive."

Strikes against the Houthis, who have weathered years of air raids by a Saudi-led coalition, would have little impact and would only raise their standing in the Arab world, said Feierstein of the Middle East Institute think-tank in Washington.

Call for 'restraint'

Yemen's neighbor Saudi Arabia is trying to extricate itself from a nine-year war with the Houthis, though fighting has largely been on hold since a truce in early 2022.

"The Kingdom of Saudi Arabia is following with great concern the military operations," a Foreign Ministry statement said after the U.S. and British strikes.

Riyadh called for "self-restraint and avoiding escalation."

U.S. and allied forces in Iraq and Syria, where they are part of an anti-jihadist coalition, have also faced stepped-up attacks since the outbreak of the war in Gaza, with Washington responding to several by bombing the sites of pro-Iran groups.

Israel has also stepped up strikes against targets in Syria, and has exchanged regular fire with Lebanon's Hezbollah over its northern border.

Washington, which has said it seeks to avoid a spreading conflict, in December announced a maritime security initiative, Operation Prosperity Guardian, to protect shipping in the Red Sea route which normally carries about 12% of global maritime trade.