DUBAI, United Arab Emirates — The U.S. Navy on Friday warned American-flagged vessels to stay out of areas around Yemen in the Red Sea and the Gulf of Aden for the next 72 hours after the U.S. and Britain launched multiple airstrikes targeting Houthi rebels.

The warning in a notice to shippers came as Yemen’s Houthis vowed fierce retaliation for the U.S.-led strikes, further raising the prospect of a wider conflict in a region already beset by Israel's war in Gaza.

The White House said the U.S. expects the Houthis to try to strike back.

"Nobody was pollyannish about the possibility that they might conduct some sort of retaliation," National Security Council spokesman John Kirby said. He added, “This wasn’t some signaling exercise. This was designed to disrupt and degrade Houthi military capabilities.”

The U.S.-led bombardment — launched in response to a recent campaign of drone and missile attacks on commercial ships in the vital Red Sea — killed at least five people and wounded six, the Houthis said. The U.S. said the strikes took aim at more than 60 targets in 16 different locations across Houthi-controlled areas of Yemen.

As the bombing lit the predawn sky over multiple sites held by the Iranian-backed rebels, it forced the world to again focus on Yemen's yearslong war, which began when the Houthis seized the country's capital.

Since November, the rebels have repeatedly targeted ships in the Red Sea, saying they were avenging Israel's offensive in Gaza against Hamas. But they have frequently targeted vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for global trade and energy shipments.

The Houthis’ military spokesman, Brig. Gen. Yahya Saree, said in a recorded address that the strikes would “not go unanswered or unpunished.”

Rep. Elissa Slotkin, a Michigan Democrat and former U.S. intelligence official, welcomed the U.S. strikes but expressed concern Iran was aiming to draw the U.S. deeper into conflict.

“We should be worried about regional escalation,” Slotkin wrote on X. “Iran uses groups like the Houthis to fight their battles, maintain plausible deniability and prevent a direct conflict with the U.S. or others. ... It needs to stop, and my hope is they’ve gotten the message.”

The British military’s United Kingdom Maritime Trade Operations, which oversees Mideast waters, reported on Friday evening a new missile attack off Yemen. It said the missile was fired toward a ship some 90 miles southeast of Aden, Yemen, while the ship was being followed by three small vessels. The shipmaster reported missiles landing in the water 400 to 500 meters away, but they caused no injures or damage, the organization said.

“Vessels are advised to transit with caution,” it warned.

Though the Biden administration and its allies have tried to calm tensions in the Middle East for weeks and prevent any wider conflict, the strikes threatened to ignite one.

Saudi Arabia — which supports the government-in-exile that the Houthis are fighting — quickly sought to distance itself from the attacks as it seeks to maintain a delicate détente with Iran and a cease-fire it has in Yemen.

It remained unclear how extensive the damage was, though the Houthis said at least five sites, including airfields, had been attacked. The White House said Friday the U.S. military was still assessing the extent the militants' capabilities might have been degraded.

U.S. Air Forces Central Command said the strikes focused on the Houthi's command and control nodes, munition depots, launching systems, production facilities and air defense radar systems. The strikes involved more than 100 precision-guided munitions including air-launched missiles and ship-and submarine launched Tomahawk land attack missiles.

The United Kingdom said strikes hit a site in Bani allegedly used by the Houthis to launch drones and an airfield in Abbs used to launch cruise missiles and drones.

Meanwhile, the U.S. Treasury Department on Friday announced it imposed sanctions on two firms in Hong Kong and the United Arab Emirates for allegedly shipping Iranian commodities on behalf of Iran-based Houthi financial facilitator Sa’id al-Jamal. Four vessels owned by the firms were also identified as blocked property.

In separate development, Iran released footage of its seizure of an oil tanker in the Gulf of Oman that once had been at the center of a dispute between Tehran and Washington.

In the footage, a helicopter hovers over the deck of the St. Nikolas. Iran’s navy seized the vessel Thursday. The vessel had been known earlier as the Suez Rajan. The U.S. seized 1 million barrels of sanctioned Iranian oil off the vessel last year.

Hussein al-Ezzi, a Houthi official in their Foreign Ministry, that “America and Britain will undoubtedly have to prepare to pay a heavy price and bear all the dire consequences of this blatant aggression.”

The Red Sea route is a crucial waterway, and attacks there have caused severe disruptions to global trade. Benchmark Brent crude oil traded up some 4% Friday at over $80 a barrel. Tesla, meanwhile, said it would temporarily halt most production at its German factory because of attacks in the Red Sea.

Meanwhile, the U.S. Navy acknowledged an attack days earlier on a ship in the far reaches of the Indian Ocean — an attack that may signal Iran's willingness to strike vessels as part of a wider maritime campaign over the Israel-Hamas conflict.

Tehran on Thursday separately seized another tanker.

In Saada, the Houthis' stronghold in northwest Yemen, hundreds gathered for a rally Friday, denouncing the U.S. and Israel. Another drew thousands in Sanaa, the capital.

Houthis now control territory that is home to some two-thirds of Yemen’s population of 34 million. War and misgovernment have made Yemen one of the poorest countries in the Arab world, and the World Food Program considers the vast majority of Yemen’s people as food-insecure.

Yemen has been targeted by U.S. military action over the last four American presidencies. A campaign of drone strikes began under President George W. Bush to target the local affiliate of al-Qaida, attacks that have continued under the Biden administration. Meanwhile, the U.S. has launched raids and other military operations amid the ongoing war in Yemen.

That war began when the Houthis swept into Sanaa in 2014. A Saudi-led coalition including the United Arab Emirates launched a war to back Yemen's exiled government in 2015, quickly morphing the conflict into a regional confrontation as Iran backed the Houthis with weapons and other support.

The conflict, however, has slowed as the Houthis maintain their grip on the territory they hold. In March, Saudi Arabia reached a Chinese-mediated deal to restart relations with Iran in hopes of ultimately withdrawing from the war.

However, an overall deal has yet to be reached, likely sparking Saudi Arabia's expression Friday of “great concern” over the airstrikes.

“While the kingdom stresses the importance of preserving the security and stability of the Red Sea region ... it calls for restraint and avoiding escalation,” its Foreign Ministry said in a statement.

Iran condemned the attack in a statement from Foreign Ministry spokesperson Nasser Kanaani.

“Arbitrary attacks will have no result other than fueling insecurity and instability in the region," he said.

In Beijing, Chinese Foreign Ministry spokeswoman Mao Ning called on nations not to escalate tensions in the Red Sea. And Russia on Friday condemned the strikes as “illegitimate from the point of view of international law.”

Oman, long a regional interlocutor for the U.S. and the West with Iran, condemned the airstrikes. It called the attack a “great concern while Israel continued its brutal war and siege of the Gaza Strip without accountability or punishment.”