Iran has detained a cargo ship with citizens of Bulgaria, Myanmar, Romania, and the UK on board in the Strait of Hormuz.

A Bulgarian captain was in command of the vessel which was sailing under the Marshall Islands' flag, Bulgarian media outlets report citing AFP news agency.

The Maersk Tigris was moving toward the island of Larak, off Iran, prior to being halted by five vessels of authorities. An official at the port of Bandar Abbas later hinted the ship could have been confiscated due to standing debts.

But according to the semi-official Fars news agency, "trespassing" in Iranian waters had been the reasons.

A website tracking the location of vessels worldwide informs that the ship's last known location was in the Persian Gulf and that it was "at anchor" at the time.

Pentagon officials quoted by the BBC announced that a US naval destroyer was monitoring the situation.

The container ship was on a timecharter to Maersk Line, the world's biggest container group. It was reportedly bound for the United Arab Emirates, but was moving close to Bandar Abbas at the time Iranian patrol vessels took over.