The U.S. and U.K. carried out strikes on targets in Yemen to retaliate for Houthi attacks in the Red Sea, President Biden announced in a statement Thursday night. The strikes were conducted with assistance from Australia, Bahrain, Canada and the Netherlands.

"These strikes are in direct response to unprecedented Houthi attacks against international maritime vessels in the Red Sea—including the use of anti-ship ballistic missiles for the first time in history," Mr. Biden said, adding he will "not hesitate to direct further measures to protect our people and the free flow of international commerce as necessary."

A Houthi military spokesperson said Friday that the attacks — 73 in all — left at least five people dead and wounded six others.

In a videotaped address, Brig. Gen. Yahya Saree said, "The American and British enemy bears full responsibility for its criminal aggression against our Yemeni people. This aggression will not go unanswered. The Yemeni armed forces will not hesitate to target sources of threat and all hostile targets - on land and at sea - in defense of Yemen, its sovereignty and independence."

Officials declined to say exactly where and what the strikes hit, but U.S. Defense Secretary Lloyd Austin said in a statement the strikes "targeted the Houthis' unmanned aerial vehicle, uncrewed surface vessel, land-attack cruise missile, and coastal radar and air surveillance capabilities."

Austin, who has been hospitalized because of an infection related to surgery to treat prostate cancer, monitored the operation in real time from the hospital, according to a U.S. defense official. The official said Austin was "actively involved" and spoke with the president twice in the past 72 hours leading up to the operation. 

U.S. Central Command said in a statement Thursday night that it struck "over 60 targets at 16 Iranian-backed Houthi militant locations" and that its targets included "command and control nodes, munitions depots, launching systems, production facilities, and air defense radar systems."

A senior military official told reporters Thursday night the strikes were launched from air, surface, and sub-surface platforms.

The U.S. and other countries had previously warned the Houthis of consequences should the attacks, which started shortly after the Israel-Hamas war began, continue.

In a joint statement, the U.S., U.K., Australia, Bahrain, Canada, the Netherlands, Denmark, Germany, New Zealand and the Republic of Korea, said the strikes were in response to "continued illegal, dangerous, and destabilizing Houthi attacks against vessels, including commercial shipping, transiting the Red Sea."

"These precision strikes were intended to disrupt and degrade the capabilities the Houthis use to threaten global trade and the lives of international mariners in one of the world's most critical waterways," the statement said.

U.K. Prime Minister Rishi Sunak in a statement called the strikes "limited, necessary and proportionate" and said the Netherlands, Canada and Bahrain provided "non-operational support."

A congressional source familiar with the matter on Thursday told CBS News that "the Biden administration briefed congressional leaders today on the plans to strike Houthi rebel targets in Yemen."

A senior military official said that, as of Thursday night, the U.S. has not seen evidence that the Houthis had retaliated on any U.S., U.K., or other vessels in the Red Sea, but added they would not be surprised to see a response.

The Houthis launched one of the largest attacks in the Red Sea yet on Tuesday. Three U.S. destroyers along U.S. F-18s and a British warship shot down 18 drones and multiple missiles launched from Houthi-controlled areas of Yemen, U.S. Central Command (CENTCOM) said in a statement. 

Tuesday's "complex attack," as CENTCOM described it, occurred within a week of a joint statement from the U.S. and several other countries warning that the Houthis would face "consequences" if the attacks continued.

"The Houthis will bear the responsibility of the consequences should they continue to threaten lives, the global economy, and free flow of commerce in the region's critical waterways," the joint statement released by the White House last Wednesday said.  

A senior administration official told reporters Thursday night that Mr. Biden convened his national security team following Tuesday's attack, where he was presented with military response options. Mr. Biden directed Austin to carry out a response at the conclusion of that meeting, leading to Thursday's strike, the official said.

Since Nov. 19, there have been at least 27 attacks on commercial shipping in the Red Sea, according to CENTCOM. The attacks have prompted several giant shipping companies to avoid the Suez Canal and transit around all of Africa instead. 

In order to curb the impact on international trade, the U.S. along with several other countries launched a maritime task force "Operation Prosperity Guardian" to patrol the Red Sea. So far, the Houthis have not stopped their attacks.

The Biden administration has focused on preventing the Israel-Hamas conflict from turning into a wider regional war across the Middle East, but since the war started, Iranian-backed proxies have been launching attacks both in the Red Sea and against U.S. forces in Iraq and Syria. 

The Pentagon has tried to retaliate against other Iranian-backed militias for the steady drumbeat of attacks in Iraq and Syria without risking escalation, but the attacks have continued. There have been at least 130 attacks by Iranian-backed militias on U.S. forces in Iraq and Syria since October 17, including at least three since Monday. 

Thursday's strike is the first time the U.S. has conducted strikes against the Houthis since the attacks began in November.

— Kristin Brown contributed reporting.