DAMASCUS, Syria – Syria's prime minister narrowly escaped an assassination attempt in the heart of the heavily defended capital Monday, state media said, laying bare the vulnerability of President Bashar Assad's regime.

The bombing, which killed several other people, highlights an accelerating campaign targeting government officials, from midlevel civil servants to the highest echelons of the Syrian regime.

State television said Prime Minister Wael al-Halqi was not hurt in the bombing, which struck his convoy as it drove through the posh Mazzeh neighborhood — home to embassies, government officials and business elites with close ties to the regime. Footage of the scene broadcast on state TV showed the charred hulks of cars and the burnt-out shell of a bus in a street littered with rubble. Eager to assure the public that Al-Halqi survived Monday's attack, the state-run Al-Ikhbariya station said the prime minister attended a regular weekly meeting with an economic committee immediately after the bombing. The station broadcast video of Al-Halqi sitting at a table with several other officials.

Later, in its evening news program, state TV showed video of Al-Halqi denouncing the attack, calling it a "terrorist and criminal act" and wishing the wounded a speedy recovery.

A government official said two people were killed and 11 wounded in the blast, while the Britain-based Syrian Observatory for Human Rights activist group put the death toll at five, including two of Al-Halqi's bodyguards and one of the drivers in his convoy.

There was no immediate claim of responsibility for Monday's attack, but bombings like the one that struck the prime minister's convoy have been a trademark of Islamic radicals fighting in the rebel ranks, such as the Al-Qaida-linked Jabhat al-Nusra.

U.N. appeals for access

At the United Nations, Secretary-General Ban Ki-moon reiterated his appeal to Syria to allow a team of experts into the country "without delay and without any conditions" to investigate allegations of chemical weapons use. He added that he takes seriously a recent U.S. intelligence report that indicates Syria has twice used chemical weapons.

The Assad government has asked for a U.N. investigation, but wants it to be limited to an incident near Aleppo in March. Ban has pushed for a broader investigation, including a December incident in the central city of Homs.

A U.N. team of experts has already begun gathering and analyzing available evidence, but Ban said onsite activities are essential.

Meanwhile, a new jihadi group calling itself the Ahrar al-Bekaa Brigades announced its formation and warned the pro-Syrian Lebanese militant Hezbollah group to stop intervening in the Syrian civil war or face attacks in Lebanon.