Heavy bombardment by forces loyal to Syrian President Bashar al-Assad have killed at least 32 civilians in the northern city of Aleppo, sources told Al Jazeera.

Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, said that the attack on Monday, targeted the Al-Shaar neighbourhood in Aleppo city’s east, which is controlled by the opposition.

Rahman said 18 civilians were killed, but sources told Al Jazeera that the fatalities were as high as 32.

“A surface-to-surface missile hit the Al-Shaar neighbourhood. People started gathering, and that’s when the army fired more missiles at the same area,” he said.

Abdel Rahman said dozens of people were wounded and others were still trapped under the rubble.

Images posted online showed screaming men carrying wounded civilians from collapsing buildings.

“The civil defence came here to pull people out of the rubble, put out fires and save people,” one emergency worker told AFP news agency.

A man standing next to a destroyed car held his head in his hands as he stared into the lobby of a partly destroyed building littered with debris.

“This is a public market and all of these people were shopping. Every time he (Assad) suffers a defeat, he takes it out on civilians,” a resident said.

Russian drones over Syria

Aleppo, once Syria’s economic powerhouse, has been devastated by fighting since 2012.

The city is now divided between government control in the west and opposition control in the east.

Much of Aleppo has been left in ruins as regime forces carry out aerial attacks and rebels retaliate, despite criticism of both sides from humanitarian organisations.

Meanwhile, two US officials told Reuters news agency that Russia has started flying surveillance missions with drone aircraft in what appeared to be Moscow’s first military air operations in Syria, since staging a rapid buildup at an airfield there.

The US officials, who spoke on condition of anonymity, could not say how many drone aircraft were involved in the surveillance missions.

The Pentagon declined to comment. Al Jazeera