Iran's Revolutionary Guard Corps Navy fired warning shots over Singapore-flagged cargo vessel in international waters in the Gulf on Thursday, prompting the cargo vessel to flee into UAE's territorial waters, a US official told Reuters, saying the account was based on preliminary information.

The UAE sent Coast Guard vessels toward the cargo ship and at some point the Iranian ships turned away, the official said. The official, who spoke on condition of anonymity, was unaware of any US Navy involvement.

Earlier, CNN reported five Iranian boats fired shots across the bow of the vessel.

There were no US personnel on the vessel, according to CNN.

The shots at the Singapore-flagged vessel were fired as US President Barack Obama and leaders from Gulf nations were set to meet at Camp David in a rare, high-profile summit on US efforts to broker a nuclear deal with Iran. The US and five other world powers are in talks with Tehran to curb its atomic programme.

Iran, currently in a standoff with a Saudi Arabia-led coalition over security inspections of its own cargo ship, last month intercepted a Marshall Islands-flagged vessel in the Strait of Hormuz. It forced that ship into Iranian territorial waters by firing shots across its bow. -Reuters