Aftermath of heavy fighting in the Syrian capital, Damascus
Syrian army helicopters pounded Damascus with rockets and heavy machine guns overnight, and tanks bombarded the capital from the ring road, to try to reverse relentless gains by rebels since much of President Bashar al-Assad's entourage was assassinated.
The unprecedented rebel momentum of the past few days has fighters boasting that Assad's grip is being pried from the country his family has ruled since his father seized power in a coup 42 years ago. But he remains a fearsome foe, reports Reuters.
"The regime has been rudderless for last three days. But the aerial and ground bombardment on Damascus and its suburbs shows that it has not lost the striking force and that it is re-grouping," opposition activist, Moaz al-Jahhar said by telephone from Damascus.
The 16-month conflict has been transformed since Wednesday, when a bomb killed four members of the president's narrow circle of kin and lieutenants, including his powerful brother-in-law, defence minister and intelligence chief.
In the days since, rebels have pushed deep into the heart of the capital and seized control of other towns. On Thursday, they captured three border crossings with Iraq and Turkey, the first time they have held sway over Syria's frontiers.
At Bab al-Hawa, a busy border post with Turkey seized by advancing fighters, rebels watched on with approval while jubilant villagers looted a duty free shop, part of the vast business empire of one of Assad's cousins.
"This is the people's money; they are taking it back," said rebel fighter Ismail. "Whoever wants to should take it."
Assad has failed to speak in public since Wednesday's blast, adding to the sense that one of the most strategically important countries in the Middle East is being torn from his grasp. A funeral was held on Friday for officials slain in the attack, but Assad did not attend and was nowhere to be seen.
The next few days will determine whether Assad's government can recover from the bombing, which wiped out much of his command structure in a single blow and destroyed his clan's decades-old aura of merciless invulnerability.
Rebels poured into the capital Damascus at the start of the week and have since been battling government forces in what the fighters call operation "Damascus Volcano".
Lightly-armed rebels have been moving on foot inside residential neighbourhoods and attacking security installations and roadblocks dotted across the capital.
Wajeeh, a private employee who did not want to give his last name, said he saw three tanks on the southern ring road that deployed late on Friday evening and were firing at the Kfar Souseh and Mezze districts in west Damascus.
"The road was cut off and troops were firing mortar rounds from next to the tanks," he said.
A resident of Mezzeh, a middle class district of high rise towers, villas and cactus fields, said army helicopters were striking the neighbourhood with heavy machineguns and rebels were firing back "uselessly" from automatic rifles.