A security team aboard a US Navy refueling ship has fired upon a small motor boat off the United Arab Emirates on Monday after it ignored warnings to halt its approach.

According to a US official at least one person was killed. U.S. Naval Forces Central Command say the motor boat ignored a series of warnings as the ship approached the Rappahannock, in waters near the UAE port of Jebel Ali.

Tensions in the area have risen since Iran threatened to close the Strait of Hormuz, through which 20 percent of the worls's oil exports pass.

Western countries have launched sanctions against Iran including blocking the country's oil exports due to Iran's nuclear programme.