Amir Hatami
Amir HatamiReuters

Iran's Defense Minister, Amir Hatami, on Wednesday "categorically rejected" accusations that Tehran was behind two tanker attacks in the Gulf of Oman last week, describing evidence presented by Washington as "unsubstantiated", AFP reported.

A Japanese-owned tanker, the Kokuka Courageous, and a Norwegian-operated one, the Front Altair, were attacked on Thursday and left ablaze as they were passing through the Gulf of Oman

Washington has blamed Iran for last week's attacks and earlier this week released images and a grainy video it alleges shows Iranians on a patrol boat removing an unexploded limpet mine attached to one of the tankers.

"Accusations levelled against Iran’s armed forces and the published film with regards to the incident (that) happened to the vessels ... are unsubstantiated and we categorically reject these accusations," Hatami said Wednesday, as quoted by the IRNA news agency.

"The armed forces and the port organization were among the first to approach the tankers after the incident for relief operations and they rescued 23 people in the first tanker," he added.

Hatami did not explicitly specify which of the two ships he was referring to, but Iran's English-language Press TV at the time broadcast footage of 23 sailors rescued from the Front Altair.

Hatami added that the Iranian forces then headed to the second tanker, but the crew said another vessel had already rescued them.

"This means Americans had arrived sooner to the scene where they claim the video was recorded," said the Iranian Defense Minister, with apparent reference to the Japanese-owned Kokuka Courageous.

Iran's Foreign Ministry had already dismissed the US allegations that it was behind the attacks as "baseless" and slammed Saudi Arabia and Britain -- where Foreign Secretary Jeremy Hunt has alleged Iran was "almost certainly" responsible for the attacks -- for following the US line.

Iran's parliament speaker has hinted that Washington could be behind the tanker attacks in an attempt to pile pressure on Tehran.

The attack last week came a month after attacks on four tankers off the coast of the United Arab Emirates on May 12. Two of the ships targeted in that attack were Saudi oil tankers that were en route to the United States.

The incidents come amid increased tensions between the US and Iran, a year after Trump withdrew from the 2015 nuclear deal between Iran and world powers and imposed several rounds of crippling sanctions on the Islamic Republic.

Iran announced last month it was suspending some of its commitments under the 2015 deal in response to the US withdrawal in May of last year.

In addition, tensions between the two longtime foes has increased after Washington sent more military forces to the Middle East in a show of force against what US officials say are Iranian threats to its troops and interests in the region.