The Islamic Revolutionary Guard Corps has seized the British oil tanker Stena Impero in the Strait of Hormuz, Iranian media reported. UK authorities said the tanker had ‘veered off course’ before capture.

The Stena Impero was headed to Saudi Arabia but left the international sea lanes and headed north towards the Iranian island of Qeshm, marine tracking data showed on Friday.

The 30,000-ton tanker is owned by Stena Bulk, and was bound for the Saudi port of Al Jubail.

Iranian state TV reported that it was seized by the IRGC naval units for “not following international maritime regulations.”

London said it was “assessing the situation following reports of an incident in the Gulf.”

This incident marks the latest escalation between the two nations as tensions continue flare in the Gulf.