BEIRUT: Violence raged across Syria Friday with opposition neighborhoods in besieged Homs enduring another day of bombardment by President Bashar Assad’s troops and Syria’s second city, Aleppo witnessing its first major attack when two bombings targeted its commercial hub, killing at least 28 people. Violence also erupted in the northern Damascus’s Al-Qaboon neighborhood as clashes were reported between loyalist and opposition troops.

An opposition activist inside Homs described a humanitarian disaster in the central city, claiming the death toll had reached 900 since the heavy assault started last Friday, adding that many deaths had been the result of a lack of medical supplies to treat the wounded.

The activist, who called himself Wael, told The Daily Star all Homs neighborhoods were being hit by air and ground shelling except for two pro-Assad areas; Al-Zahraa and Al-Nozha.

“The shelling is mostly focused on the neighborhoods of Baba Amro and Inshaat,” he said.

He added that Free Syrian Army troops were present in the city, but their movement was now limited to providing humanitarian aid to residents.

“FSA troops are besieged here like everybody else, but I learned they are planning to go on the offense in the coming few days.”

Activists earlier said shelling had started in the morning and they feared a big push was imminent. Homs has come to symbolize the center of the uprising opposing the Assad government.

Makeshift hospitals in Homs have been struggling to cope with the casualties from the government bombardments and sniper fire, and medical supplies and food are running out.

The Local Coordination Committees, an activist ground network, put the death toll Thursday alone as high as 110 by nightfall. It was impossible to verify such accounts.

The Aleppo bombings were the worst violence to hit the country’s commercial hub since the uprising began 11 months ago.

Mangled, bloodied bodies and severed limbs lay on the pavement outside the military and security service buildings that were targeted – as shown in live footage on Syrian television, which has consistently portrayed the revolt against Assad as the work of foreign-backed “terrorists.”

It was unclear who was behind the attacks. FSA commander Col. Riad al-Asaad denied his forces were responsible after another senior commander, FSA Col. Aref Hammoud told FRANCE 2 his forces had set off the twin attacks. Some opposition figures accused the government of manipulating events to discredit them.

Elsewhere, activists reported security forces opened fire in Latakia, and in the town of Dael in Deraa province, following protests after Friday prayers.

In Al-Qaboon, Damascus, members of the FSA fought for four hours with troops backed by armored vehicles who had entered the neighborhood during a protest 1.6 km from the main Abbassiyyin Square, they said.

The rebels said they had sustained several casualties but it was not known whether any had died of their wounds.

“The army used heavy machine guns and anti-aircraft guns and the rebels mostly responded with automatic rifles,” said a resident of Al-Qaboon.

Bolstered by Russian support, Assad has ignored appeals from the United States, Turkey, Europeans, fellow Arabs and other governments to halt the repression and to step down.

Foreign ministers of the Arab League, which suspended a monitoring mission in Syria last month because of the violence, will discuss a proposal to send a joint U.N.-Arab mission to Syria when they meet in Cairo Sunday, a League official said.

Turkish Foreign Minister Ahmet Davutoglu said Friday he would propose new ways to pressure Syria when he meets with U.S. Secretary of State Hillary Clinton Monday, but did not elaborate. In Geneva, the United Nations human rights said Syrian officials should face prosecution at the International Criminal Court for crimes against humanity.

“This would give a very, very strong message to those running the show,” said Rupert Colville, spokesman for U.N. High Commissioner for Human Rights Navi Pillay.

Pillay will address a U.N. General Assembly session on Syria being held in New York Monday, Colville said.