MANAMA, Bahrain — The U.S. and a host of other nations are creating a new force to protect ships transiting the Red Sea that have come under attack by drones and ballistic missiles fired from Houthi-controlled areas of Yemen, Defense Secretary Lloyd Austin announced Tuesday in Bahrain.

The seriousness of the attacks, several of which have damaged vessels, has led multiple shipping companies to order their ships to hold in place and not enter the Bab el-Mandeb Strait until the security situation can be addressed.

The U.S. military’s Central Command reported two more of the attacks on commercial vessels Monday. A strike by an attack drone and a ballistic missile hit a tanker off Yemen, at roughly the same time a cargo ship reported an explosive detonating in the water near them, the military said.

“This is an international challenge that demands collective action,” Defense Secretary Lloyd Austin said in a statement released just after midnight in Bahrain. “Therefore today I am announcing the establishment of Operation Prosperity Guardian, an important new multinational security initiative.”

There are about 400 commercial vessels transiting the southern Red Sea, an area roughly the size of Washington D.C. to Boston, at any given time, a senior military official told reporters who are traveling with Austin in the region.

Under the new mission, the military ships will not necessarily escort a specific vessel, but will be positioned to provide umbrella protection to as many as possible at a given time, the official said on the condition of anonymity to provide additional details not made public on how the new operation will work.

Mohammed Abdel-Salam, the Houthis’ chief negotiator and spokesman, on Tuesday, challenged the U.S.-created coalition, saying the Iranian-backed rebels would continue targeting Israel-linked vessels off Yemen.

“The American-formed coalition is to protect Israel and militarize the sea without any justification, and will not stop Yemen from continuing its legitimate operations in support of Gaza,” he wrote on social media platform X, formerly known as Twitter.

He said the Houthis’ attacks “are not a show of force nor a challenge to anyone,” adding, “Whoever seeks to expand the conflict must bear the consequences of his actions.”

Companies Reroute Shipping Away From Red Sea

On Tuesday the shipping company Maersk announced that for now, it had decided to re-route its ships that have been paused for days outside the strait and Red Sea, and send them around Africa through the Cape of Good Hope instead — a much longer and less efficient passage. Maersk said it welcomed the international security effort, but at the present time, the much longer route would provide “more predictable outcomes” for its customers.

In the last four weeks, Houthi militants have attacked or seized commercial ships 12 times and still hold 25 members of the MV Galaxy Leader hostage in Yemen, Austin said in remarks Tuesday in a ministerial meeting on the new maritime mission. The U.S. is still actively seeking member countries to join the mission, and increase the number of navies present and participating.

The United Kingdom, Bahrain, Canada, France, Italy, Netherlands, Norway, Seychelles and Spain have joined the new maritime security mission, Austin said. Some of those countries will conduct joint patrols while others provide intelligence support in the southern Red Sea and the Gulf of Aden.

One notably absent participant is China, which has warships in the region, but those ships have not responded to previous calls for assistance by commercial vessels, even though some of the ships attacked have had ties to Hong Kong, the military official said.

Several other countries have also agreed to be involved in the operation but prefer not to be publicly named, a defense official said on the condition of anonymity to discuss additional details of the new mission that have not been publicly announced.

The new maritime security mission will be coordinated by the already existing Combined Task Force 153, which was set up in April 2022 to improve maritime security in the Red Sea, Bab el-Mandeb and the Gulf of Aden. While the task force has primarily provided a headquarters structure to date, the goal of the new mission is to provide ships and other assets to carry out the protection. There have been 39 member nations in CTF 153, but officials were working to determine which of them would participate in this latest effort.

Separately, the United States has also called on the United Nations Security Council to take action against the attacks.

In a letter to council members obtained Monday by The Associated Press, U.S. Ambassador Linda Thomas-Greenfield said Houthi attacks targeting commercial vessels legally transiting the international waterways continue to threaten “navigational rights and freedoms, international maritime security, and international commerce.”

The 15 council members discussed the Houthi threat behind closed doors Monday but took no immediate action.

Two U.S. warships — the USS Carney and the USS Mason, Navy destroyers — are currently moving through the Bab el-Mandeb Strait to help deter and respond to attacks from the Houthis.

The move to set up the expanded operation came after three commercial vessels were struck by missiles fired by Iranian-back Houthis in Yemen on Dec. 3. Those attacks were part of an escalating campaign of violence that also included armed and other drones launched in the direction of U.S. warships.

To date, the U.S. has not struck back at the Iranian-back Houthis operating in Yemen or targeted any of the militants’ weapons or other sites. On Monday Austin did not answer a question as to why the Pentagon had not conducted a counterstrike.