Forces loyal to Libyan leader Muammar Gaddafi are fighting for control of a key crossing at the Tunisian border.

It provoked an angry protest from Tunisia as fighting spilled over into its territory.

The offensive is part of a move to root out opposition fighters on Libya's western frontier.

Al Jazeera's Sue Turton is in the opposition stronghold Benghazi and sent us this update.

[April 29, 2011]