AN unidentified vessel has been fired on off the coast of Yemen less than 24 hours after Iran seized the Marshall Islands-flagged tanker Advantage Sweet (IMO: 9587192) in the Gulf of Oman.

According to a security alert issued by the UK Marine Trade Operations office on April 28, shots were fired from three boats about 18 nautical miles south of Nishtun, Yemen.

No information has been released regarding the identity of the vessels involved or who might be behind this latest attack, however shipping operators are now on alert in the region.

Advantage Sweet remains under the control of the Iranian Navy following the seizure on April 27, however the vessel’s Automatic Identification System remains switched off.

Iran’s navy seized the Marshall Islands-flagged Advantage Sweet in international waters at about 1315 hrs local time, according to the US Navy.

The US has demanded that Iran release the Chevron chartered, Chinese-owned tanker which had been destined for Houston after it loaded 750,000 barrels of crude from Kuwait on Tuesday.

In a statement carried by Iranian state media, Iran said the tanker had collided with an Iranian vessel in the Middle Sea Gulf, injuring several people and causing two crew members from the Iranian ship to go missing.

It said the tanker then tried to escape and navigated through the Strait of Hormuz, but the Iranian navy intercepted it in the Gulf of Oman and impounded the vessel.

The US navy initially identified the naval forces of Iran’s Revolutionary Guard as the actors behind the seizure, which it said was consistent with prior events.

“After sending a P-8 Poseidon maritime patrol aircraft to monitor the situation, we have since been able to determine the IRIN (Iranian navy) conducted the seizure,” the US navy’s Fifth Fleet said on Twitter.