An oil tanker has been boarded by “armed unauthorised persons” in military uniforms and masks on Thursday morning off the coast of Oman.
The situation remains unclear but suspicion immediately fell on Iran, as the vessel was once involved in a dispute with the US Justice Department that saw a million barrels of Iranian crude oil seized.
The United Kingdom Maritime Trade Operations (UKTMO), which provides warnings to sailors in the Middle East, said the incident began early in the morning 50 miles off the coast of Oman.
UKTMO described receiving a report from the ship’s security manager of hearing “unknown voices over the phone” alongside the ship’s captain.
It said it was unable to make further contact with the vessel and that the authorities were investigating the incident.
The development comes amid high tensions in the nearby Red Sea, where attacks by Houthi rebels based in Yemen are disrupting shipping.
Oil tanker ‘struck by drone’ off coast of Oman
Who are the Houthis and why are they attacking ships in the Red Sea?
The private intelligence firm Ambrey said that “six military men” boarded the ship, which it identified as the oil tanker St Nikolas. It said that the men had covered the surveillance cameras as they boarded.
The incident began early on Wednesday morning in waters between Oman and Iran, in an area where ships coming in and out of the Strait of Hormuz pass through.
A significant proportion of the global oil trade passes through the Strait of Hormuz, despite the fact that in recent years waters around the strait have seen a series of ship seizures by Iran since the collapse of the country’s nuclear deal.
Iran and Oman did not immediately acknowledge the boarding.
The St Nikolas had earlier been named the Suez Rajan, associated with the the Greek shipping company Empire Navigation.
The ship came under the spotlight in February 2022 when the group United Against Nuclear Iran said it suspected the tanker carried oil from Iran’s Khargh Island.
For months, the ship sat in the South China Sea off the northeast coast of Singapore before suddenly sailing for the Texas coast without explanation. The vessel discharged its cargo to another tanker in August, which released its oil in Houston as part of a Justice Department order.
In September, Empire Navigation pleaded guilty to smuggling sanctioned Iranian crude oil and agreed to pay a $2.4m (£1.9m) fine over a case involving the tanker.