UK officials said two tankers were seized by Iranian forces in the Strait of Hormuz Friday — a British vessel and a Liberian-flagged ship – bringing escalating tensions between Tehran and the West in the region closer to the boiling point, according to reports.

Iran’s Revolutionary Guard took responsibility for one of the seized vessels – the 30,000-ton British ship Stena Impero, The Guardian reported.

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

The ship suddenly veered off course and into Iranian waters after the ship’s owners said it was “approached by unidentified small crafts and a helicopter … while the vessel was in international waters.”

“We are presently unable to contact the vessel which is now heading north towards Iran,” Stena Bulk, the ship’s owners, and Northern Marine, its managers, said in a statement.

Bob Sanguinetti, CEO of the UK Chamber of Shipping called the seizure a “violation of international regulations which protect ships and their crews as they go about their legitimate business in international waters,” according to the Associated Press.

Sanguinetti called on the British government to do “whatever is necessary” to exure the safe return of the ship’s crews.Iran’s Revolutionary Guard took responsibility for seizing the ship, saying it was not complying with “international maritime laws and regulations.”

The move comes just one day after authorities in Gibraltar announced they would not release the Iranian tanker Grace 1, which was seized by Britain’s Royal Marines on suspicion of shipping oil to Syria, a violation of a European Union embargo.

Iranian officials called that seizure an act of “piracy.”