A ship contracted by the US Navy has fired warning shots in the direction of two unidentified speedboats in the Gulf, US military officials say.

The incident took place in international waters dozens of miles from the Iranian coast, the US said.

In January, the US said speedboats from Iran had harassed US Navy ships in the Gulf - Iran denied issuing threats.

In the latest incident, Tehran said its vessels had had no confrontations with US ships.

The US vessel - the Westward Venture - was working for the US Military Sealift Command under a 65-day charter, an official told the BBC.

US officials say the Westward Venture used the correct measures prior to firing the shots - it sounded its horn, and gave the boats a verbal warning, before firing flares, 50-caliber machine guns and M-16s.

The speedboats withdrew soon after the warning shots were fired.

Shortly after the incident, a routine inquiry was made of the Westward Venture by Iranian authorities, according to US officials.

PHOTO CAPTION

This picture released by the US Navy in January 2008 shows a small craft suspected to be from the Iranian Revolutionary Guard Navy maneuvering near the US Navy Aegis-class cruiser USS Port Royal in the Strait of Hormuz.

BBC