Members of the Free Syrian Army (FSA),  December 15, 2011. The Free Syrian Army say they are not responsible for the recent attacks. (Sezayi Erken/AFP/Getty Images)

As reported 28 people were killed and 235 were wounded in two bomb blasts in Aleppo, the largest city in Syria and its commercial capital, according to state television.

State-run SANA said the two bomb attacks on Friday targeted a military security building, causing “great damage” to it and “nearby residential buildings.” SANA, quoting the country’s ministry of health, said that it was a terrorist attack and showed extremely graphic footage of mangled bodies and severed limbs.

The Local Coordination Committees, an activist group, said that in a separate development, “security forces started shooting at demonstrators in Marjeh neighborhood” and said 12 were killed across Aleppo, which previously was not hit by the violence plaguing the rest of the country since last March.

The Free Syrian Army collection of rebel groups said that it was not responsible for the two blasts, according to Al-Jazeera. A commander with the group said it had carried out an attack in the city, but not the bombings.

“A group from the Free Syrian Army attacked a branch of the military security and a security unit in Aleppo with only RPGs [rocket-propelled grenades] and light weapons,” commander Arif al-Hummoud told the broadcaster.

The deputy leader of the FSA, Malik al-Kurdi, told the BBC that the group carried out an attack on the same military building where the two bombs went off. “When they were gathering in a square to go to the mosques and repress demonstrations, two groups from the FSA targeted the two buildings with small arms and rocket-propelled grenade fire,” he said.

“After violent clashes, there was an explosion inside the Military Intelligence building. At first we didn’t know what it was, but we think it was the regime trying to stop the operation of the FSA,” Kurdi said.

Another FSA member, Mahir Nouaimi, said Syria carried out the attack because it seeks to “steer attention away from what it is doing in Homs,” according to AFP. Homs, a flashpoint city throughout the conflict, has been near-constantly bombarded by Syrian security forces over the past week, with estimates that more than 300 have been killed.

Western and Arab powers have been grappling with how to end the bloodshed after Russia and China last Saturday vetoed a United Nations Security Council resolution drafted by the Arab League.

“We are pursuing a path that includes isolating and pressuring the Assad regime,” U.S. White House Press Secretary Jay Carney said on Thursday, according to a transcript.