An oil tanker has been boarded in the Gulf of Oman by "unauthorized" people in military uniforms.

An advisory group run by the British military and a private intelligence firm warned the tanker has been boarded ealrier this morning.

Details remained unclear in what was apparently the latest seizure of a vessel in the tense Middle East waterways.

The UK Maritime Trade Operations (UKTMO) described receiving a report from the ship's security manager of hearing "unknown voices over the phone" alongside with the ship's captain.

The UKMTO has indicated where the incident is happening

It said it was unable to make further contact with the vessel and that the authorities were investigating the incident.

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 development comes amid high tensions in the nearby Red Sea, where attacks by Houthi rebels based in Yemen are disrupting shipping.