Washington — Washington said it would deploy 1,000 more troops to the region after renewing charges that Iran was behind a tanker attack.

The US moves came as Iran set a 10-day countdown for world powers to fulfill their commitments under a nuclear deal abandoned by Washington, saying it would otherwise surpass the uranium stockpile limit mandated by the accord.

Tensions between Tehran and Washington have escalated ever since the US quit the deal, with Washington bolstering its military presence in the region and blacklisting Iran's elite Revolutionary Guards as a terrorist organization.

On Monday, Washington further upped the ante.

"I have authorized approximately 1,000 additional troops for defensive purposes to address air, naval, and ground-based threats in the Middle East," acting Pentagon chief Patrick Shanahan said in a statement.

"The recent Iranian attacks validate the reliable, credible intelligence we have received on hostile behavior by Iranian forces and their proxy groups that threaten United States personnel and interests across the region," Shanahan said.

The United States has blamed Iran for last week's attacks on two tankers in the Gulf of Oman.

The Pentagon released new images on Monday that it said showed Iran was behind the attack on one of the ships.

The US argument centers on an unexploded limpet mine on the Kokuka Courageous tanker ship that it says was removed by Iranians on a patrol boat.

"Iran is responsible for the attack based on video evidence and the resources and proficiency needed to quickly remove the unexploded limpet mine," the Pentagon said in a statement accompanying the imagery.

The US released a grainy black and white video last week it said showed the Iranians removing the mine, but has not provided an explanation for why they allegedly did so while the US military was in the area.

The images released Monday show the site where the unexploded mine was allegedly attached, the Iranians on a patrol boat who are said to have removed it, and damage from another device that did explode. — AFP