Riad Asaad, commander of the rebel Free Syrian Army, was injured overnight in a blast that hit his car in eastern Syria, the Syrian Observatory for Human Rights watchdog said on Monday.
"An explosive device exploded last night near the car carrying Free Syrian Army commander Riad Asaad, who was conducting a tour of the town of Mayadeen in Deir Ezzor province," Observatory director Rami Abdel Rahman told AFP.
Abdel Rahman said Asaad had been wounded in the leg, and a relative of the commander told AFP that he had been transferred to Turkey for treatment after the blast.
Asaad was one of the first officers to defect from the Syrian state military to the rebel forces, joining their ranks in 2011, not long after the uprising began.
He served as commander of the rebel forces but has seen his official role diminished by the creation of a rebel military command headed by Brigadier General Salim Idriss.
Asaad has remained a prominent figure though, regularly appearing with rebel fighters on the ground.