Oil tanker and rig
Oil tanker and rigiStock

Five armed boats belonging to Iran’s Islamic Revolutionary Guard Corps unsuccessfully tried to seize a British oil tanker in the Persian Gulf on Wednesday, two US officials with direct knowledge of the incident told CNN.

The British Heritage tanker was sailing out of the Persian Gulf and was crossing into the Strait of Hormuz area when it was approached by the Iranian boats, according to the officials.

The Iranians ordered the tanker to change course and stop in nearby Iranian territorial waters. A US aircraft was overhead and recorded video of the incident, the two officials added.

The UK's Royal Navy frigate HMS Montrose had been escorting the tanker from the rear. It trained its deck guns on the Iranians and gave them a verbal warning to back away, which they did. Montrose is equipped on the deck with 30 mm guns specifically designed to drive off small boats.

UK officials had previously confirmed that the Montrose was in the region performing a "maritime security role."

The incident occurred nearly a week after the British naval force seized an Iranian oil tanker in Gibraltar on suspicion that it was carrying crude oil to Syria, in violation of EU sanctions.

The detention of the tanker angered Iran, which condemned the move as an "illegal interception" and summoned the British ambassador in protest.

Last Friday, an Iranian Revolutionary Guards commander threatened to seize a British ship in retaliation for the capture of the Iranian supertanker.

Iranian President Hassan Rouhani warned earlier Wednesday that the UK "will see the consequences" for last week’s incident.

Rouhani, speaking in a cabinet session, said, "I tell the British that they are the initiator of insecurity and you will understand its consequences later."

Wednesday’s incident also comes a day after the US Chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, said that the US and its allies were working to put together a coalition of countries to come up with a system to enforce freedom of navigation in the region amid what the US says are heightened threats from Iran.