Syrian troops launched wide-scale attacks on areas located on the outskirts of Damascus Friday, two days after Israeli jets allegedly struck a research centre at the edge of the capital.
A pro-Syrian government source told dpa that Friday's attacks came as a result of information that rebels in hideouts in the targeted areas were preparing "a terrorist attack which will target government institutions inside the capital."
"We know we are fighting guerrillas who are ready to die and not surrender... and this means it will be a long battle before we erase their existence," said the source, who requested anonymity.
Activists said Friday's violence has so far killed 33 people.
"The aerial and artillery attacks are very heavy especially on Harsata, al-Qaddam and areas which are close to the Lebanese eastern border," Damascus-based activist Haytham al-Abdallah said.
Opposition video footage, which cannot be independently verified, showed buildings in al-Qaddam ablaze and heavy shelling on Harsata, both suburbs of Damascus.
Meanwhile, tension continued over the alleged Israeli airstrike on Syrian territory on Wednesday, which targeted a military research Centre, with Syria vowing that it has the right to self-defense and with reports indicating that Israel might strike Syria again.
"Anyone would be mistaken if he/she imagines testing the capabilities of the (Syrian) armed forces," Syria's state television quoted Army chief of Staff, General Ali Abdullah Ayoub as saying, while touring a number of armed forces units in areas near Damascus.
Ayoub stressed that the war with Israel is continuous and that Syria was aware of the challenges it is facing.
Israel reportedly fears that sophisticated anti-tank and anti-aircraft weapons, supplied to conflict-hit Syria by Russia, could end up with the Lebanese Hezbollah movement, a staunch ally of Damascus and foe of Israel.