At least 11 rebel fighters were killed in a NATO air strike Wednesday in the besieged Libyan port city of Misurata, according to the BBC.

NATO said it had carried out a strike but could not confirm rebel vehicles were hit. A rebel commander and witnesses told reporters a NATO warplane had carried out the bombing.

Gaddafi's forces reportedly also shelled the frontline city on Thursday, hitting residential areas on Misurata's outskirts and wounding four people, CBS reported.

Misurata has been besieged by Gaddafi's forces for two months, and rebels desperate to hold the city had appealed for NATO to step up its air strikes there.

Survivors quoted by CNN said 11 fighters had been killed and two injured in Wednesday's strikes, while a rebel commander, Abdullah Mohammed, told the New York Times 12 had died and five had been injured in the same attack.

Rights groups say hundreds of Misurata civilians have been killed in the crossfire.

Meanwhile, fighting is reported to have spilled into Tunisian territory along Libya's western border, Tunisia's state news agency reported.

The TAP agency said forces loyal to Muammar Gaddafi had retaken a border crossing near the Tunisian town of Dehiba in fighting that killed refugees on Tunisian territory. Rebels had seized the post a week ago.

The fighting pushed about 1,000 Libyans from Wezen in western Libya to take refuge in the Tunisian desert, TAP reported.