The United Kingdom Maritime Trade Operations (UKMTO) agency has said it had received a report of a tanker being fired upon by what it said “two gunboats linked to Iran’s Revolutionary Guards (IRGC)” 20 nautical miles northeast of Oman, Reuters reports.

The captain of the tanker said the two gunboats opened fire without issuing a radio challenge, UKMTO has said in its advisory note, adding that the vessel and its crew were reported safe.