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. The Iranians ordered the tanker to change course and stop in nearby Iranian territorial waters, according to the officials. A US aircraft was overhead and recorded video of the incident.
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."
Iranian President Hassan Rouhani warned earlier Wednesday that the UK "will see the consequences" after Gibraltar officials and UK Royal Marines seized an Iranian oil tanker bound for Syria last week, according to Rouhani's press office.
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."
US Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford said Tuesday 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.
"We had a discussion today, the Secretary of State, the Secretary of Defense and I and we are engaging now with a number of countries to see if we can put together a coalition that would ensure freedom of navigation both in the Straits of Hormuz and the Bab el Mandeb," Dunford said following an awards ceremony for his Finnish counterpart.
"I think what we'll do is, we certainly from the United States perspective would provide maritime domain awareness and surveillance," he said, adding that naval vessels would escort commercial ships that shared a country of origin, if required.
"Escorting in the normal course of events would be done by countries who have the same flag so a ship that is flagged by a particular country would be escorted by that country and I think what the United States can provide is domain awareness, intelligence, surveillance, reconnaissance and then coordination and patrols for other ships that would be in the area would be largely coalition ships," Dunford said.
This story is breaking and will be updated.