Syrian forces struck back against rebels on Thursday with attack helicopters and shelling in Damascus, one day after an audacious rebel attack in the capital killed three leaders of the regime and left President Bashar Assad's hold on power increasingly tenuous.
The whereabouts of President Bashar Assad, his wife and their three young children were not known. Although Assad does not appear in public frequently, his absence was notable following such a serious blow his inner circle.
Thousands of Syrians streamed across the Syrian border into Lebanon, fleeing as fighting in the capital entered its fifth straight day, witnesses said.
Residents near the Masnaa crossing point — about 40 km from Damascus — said hundreds of private cars as well as taxis and buses were ferrying people across.
Maj. Gen. Robert Mood, the Norwegian head of nearly 300 unarmed U.N. observers in Syria, condemned the violence and encouraged a diplomatic solution, which appears increasingly out of reach. He spoke just hours before a planned U.N. Security council vote on whether to renew the mission's mandate, which expires Friday, and impose new sanctions on the Damascus regime.
"It pains me to say, but we are not on the track for peace in Syria," Mood said in Damascus.
The U.N. vote had been scheduled for Wednesday, but was postponed after key Western nations and Russia failed to agree the text of a resolution aimed ending the escalating violence. Russia, a longtime ally of Syria, has stood by the Syrian regime and vowed to veto any measures that could lead to international military intervention.
In Thursday's fighting in Damascus, government forces fired heavy machine guns and mortars in battles with rebels in a number of neighbourhood in the capital, the Britain-based Syrian Observatory for Human Rights said.
Adding to the confusion, Syria's state-run TV warned citizens that gunmen were disguising themselves in military uniforms to carry out attacks.
"Gunmen are wearing Republican Guard uniforms in the neighbourhoods of Tadamon, Midan, Qaa and Nahr Aisha, proving that they are planning attacks and crimes," Sana said.
Many residents were fleeing Damascus' Mezzeh neighbourhood after troops surrounded it and posted snipers on rooftops while exchanging gunfire with opposition forces.
The Observatory, which relies on a network of activists inside Syria, said rebels damaged one helicopter and disabled three military vehicles.
Rebels fired rocket-propelled grenades at a police station in the Jdeidet Artouz area, killing at least five officers, the group said.
Activist claims could not be independently verified. The Syrian government bars most media from working independently in the country.
The unarmed observers were authorised for 90 days to monitor a cease-fire and implementation of Kofi Annan's six-point peace plan, but the truce never took hold and the monitors have found themselves largely locked down because of the persistent violence.
Mood said the observers "will become relevant when the political process takes off."
Syria's 16-month crisis began with protests but it has evolved into a civil war, with rebels fighting to topple Assad.
Wednesday's rebel bomb attack on high-level crisis meeting struck the harshest blow yet at the heart of Assad's regime. The White House said the bombing showed Assad was "losing control" of Syria.
Syrian TV confirmed the deaths of Defence Minister Dawoud Rajha, 65, a former army general and the most senior government official to be killed in the rebels' battle to oust Assad; Gen. Assef Shawkat, 62, the deputy defence minister who is married to Assad's elder sister, Bushra, and is one of the most feared figures in the inner circle; and Hassan Turkmani, 77, a former defense minister who died of his wounds in the hospital.
Also wounded were Interior Minister Mohammed Shaar and Maj. Gen. Hisham Ikhtiar, who heads the National Security Department. State TV said both were in stable condition.
Rebels claimed responsibility, saying they targeted the room where the top government security officials in charge of crushing the revolt were meeting.
Activists say more than 17,000 people have been killed since the uprising began in March 2011, most of them civilians. The Syrian government says more than 4,000 security officers have been killed. It does not given numbers of civilian dead.