BEIRUT: Two car bombs exploded in southern Syria and a rocket slammed into a building in the north, killing at least 12 people in a spike in civil war violence Friday that Syrian state media blamed on rebel fighters trying to topple President Bashar Assad.

The rocket attack in the northern city of Aleppo and the suicide car bombings in Daraa, south of Damascus, occurred during a particularly bloody week nearly two years after an uprising began against Assad's regime.

On Thursday, opposition activists said pro-government militia swept through a town in central Syria, torching houses and killing more than 100 people.

Both sides have been blaming each other for the recent attacks, and it was the second time in a week that the government accused rebels of firing rockets.

The state-run SANA news agency said the morning attack in Aleppo was carried out by terrorists, a term the regime uses for rebels. But the Local Coordination Committees of Syria, an activist group, and the Aleppo Media Center, a network of anti-regime activists, accused the government of launching an airstrike.

On Tuesday, 87 people were killed in twin blasts at Aleppo University. The regime said rebels hit the university with rockets. Rebels said the deaths resulted from regime airstrikes.

Syria's state-run TV claimed that shortly after the rocket hit the building in Aleppo, militants linked to an al-Qaida group detonated cars filled with explosives near a mosque in Daraa as worshippers were leaving following Friday prayers.

Video broadcast on Syrian state TV showed several floors of the targeted building collapsed in a government-controlled area of Aleppo, Syria's largest urban center and main commercial hub. The video showed a man carrying a baby out of the damaged building and another man was seen clutching his head as blood ran down his forehead. Residents were also seen looking for people buried in the rubble. At least one injured person on a stretcher was seen being carried away in a Red Crescent ambulance.

State TV reports said both attacks caused many casualties, but it was not immediately known how many people were killed or wounded in the two cities - both major fronts in the civil war.

The Britain-based Syrian Observatory for Human Rights said 12 people were killed in the Aleppo attack and dozens were wounded. The group relies on reports from activists on the ground.

Government troops and rebels have been locked in a deadly stalemate in Aleppo and other areas in the north since last summer. Six months later, the rebels hold large parts of the city. Still, they have been unable to overcome the regime's far superior firepower.

With the two sides deadlocked on the northern front, rebels have increasingly targeted state security facilities and government institutions in other parts of the country, including in the capital, Damascus.

Suicide attacks have been a hallmark of the Islamic rebel units that have been fighting alongside other

opposition fighters.

State TV said fighters with Jabhat al-Nusra, a group the U.S. has declared a terrorist organization, were behind the twin blasts in Daraa.

Daraa is the birthplace of the revolt that erupted in March 2011. It began as peaceful protests against Assad's rule but quickly turned into a civil war after a brutal government crackdown on dissent More than 60,000 people have been killed in the violence, according to a recent United Nation's estimate.

Also on Friday, fighting between Syrian rebels and Assad's loyalists flared in a Palestinian refugee camp in Damascus, killing 12 people and wounding at least 20 others, a U.N. refugee agency said. Children were among the casualties, according to a statement issued by the U.N. Relief and Works Agency. The agency called on both sides to "pull back from civilian areas, including refugee camps."

The Palestinian camp called Yarmouk has been the scene of heavy clashes between rebels and regime loyalists since mid-December, when opposition fighters moved into the camp during an attempt to storm the capital.

About half of Yarmouk's 150,000 residents have fled since fighting erupted in mid-December, according to UNRWA, which administers Palestinian camps in the Middle East. Some sought refuge in neighboring Lebanon, and others found shelter in UNRWA schools in Damascus and other Syrian cities.

Dozens have been killed in the fighting, although the United Nations did not provide an exact figure of casualties in Yarmouk violence, which has included airstrikes and artillery shelling from the Syrian military.

On Syria's northern border with Turkey, regime fighter jets pounded villages in rebel-held areas in Latakia province, dropping makeshift bombs made from hundreds of pounds (kilograms) of explosives stuffed into barrels, Turkey's state-run Anadolu agency said. The so-called barrel bombs were used in strikes on targets in Latakia Friday, the agency said, adding the regime's assault included military helicopters.

The shelling of Latakia could be heard across the border in the Turkish province of Hatay, according to the news report, which also reported heavy clashes between government troops and rebels in Syria's northern Idlib province, also along the border with Turkey.

There were no reports of any deaths in the fighting. Ambulances were sent to the border region to bring wounded Syrians to hospitals in Turkey, the agency said.