DAMASCUS, Syria -- An explosion ripped through a busy intersection in the Syrian capital Friday, hitting a police bus and killing at least 11 people and possibly many more in an attack that left pools of blood in the streets and marked the second deadly attack in the capital in as many weeks, Syrian authorities said.
Interior Minister Mohammed Shaar blamed a suicide bomber for the blast, which comes exactly two weeks after twin bombings in the capital killed 44 people. The bombings mark a dramatic escalation of bloodshed as Arab League observers tour the country to investigate President Bashar Assad's bloody crackdown on a 10-month-old popular revolt.
"He detonated himself with the aim of killing the largest number of people," Shaar said.
Syrian television showed residents and paramedics carrying human remains, holding them up for the camera. Other footage showed a police bus with blood on its seats, and cars with blown-out windows and riddled with shrapnel.
An Associated Press reporter at the scene said the blast also damaged a nearby police station, shattering its glass, and that there was blood and flesh in the streets. Police cordoned off the area with yellow police tape.
Shaar said 11 people have been confirmed dead. Authorities believe another 14 were also killed, based on human remains from the scene, which would bring the death toll to 25, state TV said. More than 60 people were wounded.
In a sign of just how polarized Syria has become, the opposition has questioned the government's allegations that terrorists are behind the attacks -- suggesting the regime itself could have been behind the violence to try to erode support for the uprising and show the observer team that it is a victim in the country's upheaval.
The government has long contended that the turmoil in Syria this year is not an uprising but the work of terrorists and foreign-backed armed gangs.
A Syrian official, speaking on condition of anonymity because he was not allowed to speak publicly to the media, said the target of the attack appeared to be a bus carrying policemen.
The official also said that a smaller bomb exploded Friday in the Damascus suburb of Tal, killing a girl. Security experts dismantled another bomb in the same area, he said.
The Arab League observers started work Dec. 27, and violence has spiked since then. Syrian activists saying up to 400 people have been killed since Dec. 21. The U.N. says the overall toll since the revolt began is more than 5,000.
The blast went off at an intersection in the central Damascus neighborhood of Midan on Friday, the start of the weekend in Syria and much of the Arab world. Midan is one of several Damascus neighborhoods that has seen frequent anti-Assad protests on Fridays since the uprising began in March.
"I heard the explosion at about 11:15 and came running here. I found bodies on the ground including one of a man who was carrying two boxes of yogurt," Midan resident Anis Hassan Tinawi, 55, told The Associated Press.
Compared to many parts of the country which have been convulsed by the 10-month old uprising, Damascus has been relatively quiet under the tight control of ruthless security agencies loyal to Assad.
But violence in the capital has been on the rise over the last two months. On Dec. 23, according to the Syrian authorities, two car bombers blew themselves up outside the heavily guarded compounds of the country's intelligence agencies, killing at least 44 people and wounding 166.
If the official account is correct, they would be the first suicide bombings during the uprising. State-run TV said the al-Qaida terrorist network was possibly to blame.
Adding to the bloodshed in recent months, dissident soldiers who broke from the military to side with peaceful protesters have launched attacks on government sites, raising fears of civil war.
Air force Col. Riad al-Asaad, leader of the main armed group fighting the regime, denied responsibility for Friday's bus bombing in an interview with pan-Arab Al-Jazeera TV.
He said his organization, the Free Syrian Army, "doesn't have the experience to carry out such explosions" and said the regime "is the plotter for this attack." He spoke from Turkey, where the group is based.