Syrian rebels have threatened to attack Hezbollah leader Hassan Nasrallah if he continues to aid the regime of Syrian President Bashar Assad.
A message published on Thursday by the Joint Command of the Free Syrian Army said that Nasrallah was not immune from attack and that the rebels knew how to reach him.
In the message, Nasrallah was referred to as a "criminal."
Addressing Nasrallah, the message said "your era has practically ended."
"Anyone who dares to attack our people and our land will pay a hefty price," the message said.
Citing opposition sources, Al-Arabiya reported that rebels have shelled Hezbollah positions in Syria and Lebanon in response to Hezbollah support for the Assad regime.
Also on Thursday, a car bomb exploded near Syria's ruling party headquarters in Damascus, killing at least 53 people and scattering mangled bodies among the blazing wreckage on one of the bloodiest days in the capital since the uprising began almost two years ago.
Elsewhere in the city, two other bombs struck intelligence offices, killing 22, and mortar rounds hit the Syrian military's central command, activists said.
Syrian state media said the car bombing near the Baath Party headquarters and the Russian Embassy was a suicide attack that killed 53 civilians and wounded more than 200, with children among the casualties.
Anti-regime activists put the death toll at 61, which would make it the deadliest Damascus bombing of the revolt that began in March 2011.