Libya: Forces mass for Sirte offensive

Interim authority forces are massing outside the Libyan city of Sirte, ready for a fresh assault on the pro-Gaddafi stronghold.

The BBC's Jonathan Head, just outside the city, said that troops were facing extraordinary resistance in areas of the city in defence of what seems a lost cause.

On Friday, the two sides battered each other with mortar shells, rockets and tank fire in what transitional government (NTC) forces described as the final assault on Sirte, some 360km (225 miles) east of the capital, Tripoli.