US looks to build 'international consensus' around tanker attacks, says Iran interfered with the damaged ships The U.S. said Iranian boats have kept salvage tugs from moving one damaged ship.

The U.S. is looking to build an "international consensus" around Thursday's tanker attacks in the Gulf of Oman that the U.S. has blamed squarely on Iran. Meanwhile, in the aftermath of the attack, Iranian small boats have prevented salvage tugs from moving one of the damaged ships to a port, according to a U.S. official.

Acting Defense Secretary Patrick Shanahan highlighted to reporters on Friday that the attacks were not only a "U.S. situation," saying the focus now is to "build international consensus to this international problem."

"When you look at the situation, a Norwegian ship, Japanese ship, Kingdom of Saudi Arabia, UAE..." Shanahan said, listing some the countries that owned ships attacked in Middle Eastern waters Thursday and in another attack a few weeks prior.

"Fifteen percent of the world's oil flows through the Strait of Hormuz," Shanahan continued. "So, we obviously need to make contingency plans should the situation deteriorate, but we also need to broaden our support for this international situation."

He said the effort to declassify intelligence and release it publicly was part of the effort to build international consensus.

On Thursday evening, U.S. Central Command released video taken from a U.S. Navy P-8 surveillance aircraft showing what they said were Iranian small boats attempting to remove an unexploded mine from the side of the Kokuka Courageous -- one of the two ships attacked earlier that day. CENTCOM also released images of that ship, showing where one mine had exploded and another had not.

In a statement, the United Kingdom's Foreign Office said it was “almost certain that a branch of the Iranian military -- the Islamic Revolutionary Guard Corps -- attacked the two tankers," adding that "no other state or non-state actor could plausibly have been responsible."

But the German Foreign Minister was not as convinced, saying video released by CENTCOM was "not enough" for Germany to make a final assessment.

Iranian officials have flatly denied any involvement in the attacks.

Iranian interference in aftermath of tanker attacks

In the day following the attacks, Iranian small boats have prevented salvage tugs from towing the other damaged ship, the Front Altair, as they had been contracted to do, a U.S. official told ABC News.

The Front Altair suffered significant damage after the explosion of two to three mines triggered a massive fire on board the ship. While it was feared that that tanker would sink, officials said it now appears salvageable. But the salvage tugs have been told by Iranians that they cannot move the tanker, the official said.

The 23 mariners on board the Front Altair were rescued shortly after Thursday's attack by the Hyundai Dubai, but Iranians aboard small boats quickly demanded the crew be turned over to their custody. The master of the Hyundai Dubai contacted the headquarters of his shipping company in Seoul and was instructed not to turn the crew over to the Iranians. However, the ship's master felt he had no choice to comply with the Iranian demands. So the crew was taken to an Iranian port where they remained on Friday.

While the owners of the Front Altair said the mariners would be repatriated, there have been no indications yet from Iran that that is the case.

According to a separate U.S. official, crew members from the Kokuka Courageous returned to their tanker very early Friday morning and contracted a tug to pull the ship back to the United Arab Emirates.

Several Iranian small boats and an Iranian tug “offered assistance,” but that assistance was declined by the ship’s master. As the Iranians on those vessels kept insisting that they wanted to assist, the U.S. Navy destroyer, USS Bainbridge, made a bridge to bridge communication with the Iranians and told them that no assistance was required. The official added that the Iranians did not try to force themselves onto the ship because of the Bainbridge’s presence.

On Thursday, it was the Bainbridge that rescued the Kokuka Courageous's 21-person crew, treating minor injuries.

The Bainbridge, along with another U.S. Navy destroyer, USS Mason, remain near the Kokuka Courageous. The USS Lincoln carrier strike group, which was deployed to the Middle East in response to threat streams emanating from Iran in early May, is also in the vicinity.