President Donald Trump is warning of more strikes against Iran as a key group of Marines and sailors has left the Middle East region.

Two ships with the USS Tripoli Amphibious Ready Group, USS Tripoli and USS Rushmore, have exited the U.S. Central Command area of operations and are now operating in the Indian Ocean after months of supporting the war against Iran, two defense officials tell Newsmax.

The third ship with the amphibious ready group, USS New Orleans, is still in the Arabian Sea in the U.S. Central Command but is expected to move into the U.S. Pacific Command soon.

The USS Tripoli Amphibious Ready Group carried about 3,500 sailors and Marines from the 31st Marine Expeditionary Unit to the Middle East. The force helped carry out strikes against Iran and enforce the U.S. blockade in the Strait of Hormuz.

The move comes as U.S. officials say an Iranian assault on three commercial ships Monday night ignited the fresh exchange of fire.

More than 20 U.S. Navy ships are now patrolling the waters after Tuesday's attack on Iran hit more than 80 targets — including radar sites, Islamic Revolutionary Guard Corps small boats, and anti-ship and air defense systems, the U.S. Central Command said in posts on X.

Iran retaliated with strikes against Kuwait and Bahrain and threatened to close the Strait of Hormuz.

Trump on Wednesday renewed threats to strike Iran's civilian infrastructure, including electric plants and desalination plants, and to seize the oil production hub on Kharg Island.

"We attacked Kharg island last night ...There's not a thing they can do about it," he said.

The U.S. had already bombed military targets on the island during the first two months of the war.

Current and former defense officials say seizing the island would require boots on the ground — likely tens of thousands of Marines and soldiers on Kharg Island and the surrounding areas.

The last ships of the USS Boxer Amphibious Ready Group arrived in the region last week with roughly 4,500 Marines and sailors, according to the U.S. Central Command, so commanders have roughly a similar number of Marines in the region now as they did during the last time administration officials floated the idea of taking Kharg Island.

Kharg Island is roughly the same size as the island of Iwo Jima in Japan.

During World War II, it took 70,000 Marines to take the island of Iwo Jima in a battle that lasted about a month. Thousands died in that fight.

Reuters contributed to this report.