Libyan rebels battle for oil port Ras Lanuf

Libyan rebels have defied their commanders in Benghazi to begin a battle for oil port Ras Lanuf, as the continue in their struggle to take control of the country from Col Muammar Gaddafi.

The Libyan army is reported to have used helicopters and artillery fire after the rebels attacked a military base on the outskirts of the city.

John Simpson reports.