How many people got wounded in this incident?

At least two Libyan rebels were killed Thursday when a NATO airstrike hit one of their tank positions near the eastern town of Brega. More than 20 other people were wounded. The victims were taken to a hospital in Ajdabya. The North Atlantic Treaty Organization says it is investigating the incident. Rebels have been fighting forces loyal to Libyan leader Muammar Gaddafi to retake control of Brega. Recently, rebel leaders criticized NATO for failing to protect civilians and for not striking Libyan forces quickly or forcefully enough.