The U.S. Navy has turned back 27 ships trying to enter or exit Iranian ports since an American blockade outside the contested Strait of Hormuz began about a week ago, the military’s Central Command said on Monday.

A U.S. military official also said on Monday that a team of Marines was searching as many as 5,000 containers aboard the Touska, an Iranian cargo ship that the Navy disabled and seized in the Gulf of Oman on Sunday after it tried to evade the blockade.

It was the first time a vessel was reported to have tried to evade the U.S.-imposed blockade on any ship entering or exiting Iranian ports since it took effect last week.

American officials will determine what to do with the disabled vessel once the search is completed, a U.S. military official said on Monday, speaking on the condition of anonymity to discuss operational matters. One option would be to tow the stricken ship to Oman, independent specialists said. An alternative would be to let the Touska steam to an Iranian port, if it can.

The ship’s crew will be returning to Iran soon, a second U.S. military official said.

“The message is out that most ships are not wanting to go out there,” Kevin Donegan, a retired vice admiral and former top Navy commander in the Middle East, said in an interview on Monday.

The Touska’s captain had ignored multiple radioed American warnings to halt.

The guided-missile destroyer Spruance, one of more than a dozen Navy warships enforcing the U.S. blockade, ordered the vessel’s crew to evacuate its engine room. The Spruance then fired several rounds from its Mk-45 gun into the ship’s propulsion system as it steamed toward the port of Bandar Abbas in Iran, Central Command said in a statement that included a video of the firing.

The Mk-45 deck gun, located on the Spruance’s bow, can shoot 16 to 20 rounds per minute. The 5-inch-diameter projectiles it fires weigh about 70 pounds each and contain the equivalent of roughly 10 pounds of TNT.

A spokesman for Iran’s military reiterated a threat on Monday to “take the necessary action against the U.S. military” in response to the ship’s seizure, Iran’s state broadcaster reported. Iran has waited to take action so far in order to protect the ship’s crew and some of their family members, he said.

Social media accounts in Iran said that Tehran had launched retaliatory drone strikes against U.S. Navy ships in the region, a purported attack that the Pentagon said on Monday never happened.

The Touska was one of “several vessels of interest” that U.S. intelligence analysts have been monitoring in recent days, both inside and outside the blockade boundary, the U.S. military official said.

“We have eyes on every single one of them,” Adm. Brad Cooper, the head of Central Command, told reporters on Friday.

Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, said on Thursday that U.S. military commanders elsewhere in the world, and especially in the Indo-Pacific region, would “actively pursue any Iranian-flagged vessel or any vessel attempting to provide material support to Iran.”

John Ismay and Sanam Mahoozi contributed reporting.