Iranian forces this afternoon boarded a Marshall-Islands flagged container ship after firing warning shots.

The Pentagon said the Maersk Tigris was boarded by Iranian forces in the Stait of Hormuz in the Gulf.

Colonel Steve Warren, a Pentagon spokesman, said the cargo ship's master had initially refused an Iranian order to move further into Iranian waters, but after the warning shots were fired the MV Maersk Tigris complied.

The ship issued a distress call and US Naval Forces Central Command, based in the area, sent a US destroyer and an aircraft to the area of the incident to monitor the situation.

No one was injured.

The ship is managed by Singapore-based Rickmers Ship Management. A Rickmers Group spokeswoman declined to comment when contacted by Reuters about the vessel.

A spokesman for the world's biggest container group Maersk Line said the vessel was on time charter to Maersk Line, declining further comment.

The vessel was bound for Jebel Ali in the United Arab Emirates, although it was still close to the Iranian port of Bandar Abbas when it was boarded.

Its previous port was listed as Jeddah in Saudi Arabia.

Iran said its Islamic Revolutionary Guards Corps seized the ship legal reasons,.

The report, which described the ship as "an American cargo vessel with a Marshall Islands flag", said there were 34 crew members on board who were mostly Europeans. The source told IRNA the incident was a civil matter with no military or political dimension.

The IRGC is Iran's elite military force and operates its own land, naval and air forces under a separate command chain from the regular armed forces.

Iran's semi-official Fars news agency earlier said the ship was seized after a court order was issued for its confiscation, referring to what it called financial differences between Iran's Ports and Maritime Organization and the vessel's owner.