Sayyed Hassan Nasrallah, leader of the Lebanese Shi'ite militant movement Hezbollah, said on Sunday the rebels in Syria could not emerge victorious from the 21-month-long uprising against President Bashar al-Assad.
Nasrallah, a staunch ally of Assad, said: "The situation in Syria is getting more complicated (but) anyone who thinks the armed opposition can settle the situation on the ground is very very very mistaken."
Syrian rebels accuse the Shi'ite Muslim group of sending fighters to neighbouring Syria to help Assad overcome the largely Sunni Muslim revolt. Hezbollah denies these accusations.
The uprising started as peaceful demonstrations calling for greater freedoms but turned into an armed insurgency largely in response to heavy crackdown and attacks by Assad forces.
The revolt pits majority Sunnis against Assad's Alawite sect, an offshoot of Shi'ite Islam. With Sunni-Shi'ite sectarian tension smouldering in the region, Syria's conflict has drawn Sunni radicals from elsewhere into rebel ranks.