AT LEAST 25 people were reportedly killed or wounded after a suicide bomber blew himself up in central Damascus on Friday, the second such attack on the Syrian capital in a fortnight.
The bomb was detonated at a set of traffic lights in the historic district of al-Midan, just south of Damascus's ancient walled city, state television reported.
Video footage indicated that a police bus had borne the brunt of the blast. Reduced to a shell, its seats were soaked in blood and covered in shards of glass.
The television station claimed that the majority of the casualties were civilians, saying that the attack took place "in a heavily populated working-class neighbourhood near a school". More than 46 people were also wounded in the attack, it added.
There was no independent confirmation of the number of fatalities. The regime was quick to blame the attack on "terrorists", which it says have been at the forefront of the uprising against President Bashar al-Assad that erupted last March.
The attack came exactly a fortnight after two booby-trapped cars, allegedly driven by suicide bombers, exploded in front of government intelligence buildings in Damascus on December 23rd, killing 44 people.
Friday's attack, like the one before it, coincided with mass protests called to demand Mr Assad's overthrow and opposition officials claimed the blast was planned by the government to distract attention from the demonstrations.
Protests after noon prayers on Fridays have traditionally drawn the largest turnouts of the uprising, and organisers said they expected hundreds of thousands to take to the streets.
December's attack saw the government and the opposition each accuse each other of being responsible. The regime claimed that the double bombings were carried out by al Qaeda, which it said had infiltrated opposition ranks.
But the opposition claimed that the attacks were the work of the government itself and were ordered as part of a conspiracy to discredit the protest movement and rally the country behind Mr Assad.
Friday's attack came as Arab League observers continued a mission in the country to monitor the regime's compliance with a regional peace plan designed to end the violence, which has claimed more than 5,000 lives in the past 10 months according to UN estimates.
There were unconfirmed reports that a group of observers came under fire from pro-regime gunmen as they entered the restive Damascus district of Arbeen on Friday morning.
The Arab League has come under growing pressure to withdraw its mission amid claims that the monitors had failed to end the violence and were giving Mr Assad diplomatic cover to continue killing civilians.
Amid the carnage, the opposition was given a major boost as it emerged that one of Mr Assad's generals had defected to join the rebel Free Syrian Army.
The officer, identified by al Jazeera as Mustafa Ahmed el-Sheikh, was the most senior yet to desert his post. Gen Sheikh called on other officers to join him.
A key opposition strategy for toppling Mr Assad revolves around persuading a critical mass of his armed forces to defect, thereby toppling one of the regime's most important pillars of support.