Iranian warships have seized control of a cargo vessel in the Strait of Hormuz on charges of breaching the country's territorial waters.
A US defence department spokesman said on Tuesday that the Iranian navy was taking a Marshall Islands-flagged cargo vessel, the MV Maersk Tigris, to the southern port city of Bandar Abbas in the Gulf after it entered its waters.
Pentagon spokesman Colonel Steve Warren, who said there were no Americans on board, said the vessel had been boarded by the Iranian navy and no injuries had been reported.
Warren said the ship issued a distress call and US Naval Forces Central Command, based in the area, had sent a US destroyer and an aircraft to the area of the incident to monitor the situation.
Al Jazeera's Alan Fisher, reporting from Washington, said the White House and Pentagon were informed of the incident and were investigating the matter.
Fisher said there were unofficial reports that shots had been fired over the vessel prior to the seizing.
He also said that 34 people were believed to be on board but none were US nationals.
The Reuters news agency had earlier reported that the vessel was a US cargo ship.
At its narrowest point, the strait is 33km across and consists 3.2km wide navigable channels for inbound and outbound shipping as well as a 3.2km-wide buffer zone.
Source: Al Jazeera and agencies