Iran’s Revolutionary Guards said yesterday they captured a British-flagged oil tanker in the Gulf after Britain seized an Iranian vessel earlier this month, further raising tensions along a vital international oil shipping route, reports Reuters.

Britain said it was urgently seeking information about the Stena Impero after the tanker, which had been heading to a port in Saudi Arabia, suddenly changed course after passing through the Strait of Hormuz at the mouth of the Gulf.

The Revolutionary Guards said they seized the tanker at the request of Iranian maritime authorities for “not following international maritime regulations,” state television reported.

Citing a maritime tracking website, the BBC also reported a second tanker with UK links has made a sharp turn towards Iran. The Ministry of Defence said it was aware of reports about a second vessel -- the Liberian MV Mesdar is British owned.

Relations between Iran and the West have been increasingly strained since British naval forces seized an Iranian tanker in Gibraltar on July 4 on suspicion of smuggling oil to Syria in breach of European Union sanctions.

Iran said it would retaliate and days later three Iranian vessels tried to block a British-owned tanker passing through the Strait of Hormuz. But on that occasion, the Iranian vessels backed off when confronted by a British Royal Navy warship, according to Reuters.

“We are urgently seeking further information and assessing the situation following reports of an incident in the Gulf,” a spokesman for Britain’s Ministry of Defence said yesterday.

A person familiar with the matter said a meeting of the British government’s emergency committee was being held.

Prime Minister Theresa May’s office declined to comment.

Refinitiv data showed the Stena Impero was a British-flagged vessel owned by Stena Bulk. It showed the vessel’s destination as the Saudi port of Jubail on the Gulf.

The map tracking the ship’s course showed it veering off course with a sharp turn north at about 1517 GMT on Friday and heading toward the Iranian coast.

In a statement, the ship’s owner Stena Bulk and operator Northern Marine Management said that at approximately 4 pm BST (12 pm ET) the Stena Impero was “approached by unidentified small crafts and a helicopter during transit of the Strait of Hormuz while the vessel was in international waters,” reports CNN.

There are 23 seafarers aboard the ship, they added, saying that they have are currently unable to make contact with the vessel, which is now heading north towards Iran.

A UK government official told CNN that the UK has convened a COBRA meeting -- an emergency response committee that meets when there’s a domestic or international crisis -- on the seized tanker.

The ship’s seizure is yet another in an accelerating series of recent maritime episodes involving Iran.

On Thursday, the US Navy destroyed an Iranian drone using electronic jamming, a US defense official told CNN. The crew of the USS Boxer took defensive action against the Iranian unmanned aerial vehicle after it came close to the US naval ship, the official said.

Chief Pentagon Spokesperson Jonathan Hoffman said then that the USS Boxer had been in international waters where it was “conducting a planned inbound transit of the Strait of Hormuz.”

US President Donald Trump said the Iranian drone was “threatening the safety of the ship and the ship’s crew” and was “immediately destroyed.”

However, Iranian officials say none of their drones have been downed.

In another incident last week, armed Iranian boats tried unsuccessfully to impede the passage of a British oil tanker in the Persian Gulf, according to two US officials with direct knowledge of the incident.

And in June, tensions between the US and Iran escalated into a military standoff after an American drone was shot down by Iran over the Strait of Hormuz, one of the world’s most vital shipping routes.