Syrian army helicopters dropped two barrel bombs on a crowded square in a rebel-held neighborhood in the northern city of Aleppo, killing at least 25 civilians, activists said Friday.

Among the casualties in the attack, which took place on Thursday night, were people sitting on a bus and others coming to the square to collect water, the activists said.  The attack came just hours after rebels bombarded the capital, Damascus, killing nine people there Thursday.

The Aleppo attack coincided with a wider government offensive against rebel positions across Syria, where the brutal civil war has lately been overshadowed by the rampage by militants from the Islamic State group, which has captured large swaths of territory both in Syria and neighboring Iraq.

The United Nations estimates that more than 220,000 people have been killed in Syria's nearly 4-year-old conflict.

Three sources provided different death tolls from the barrel-bombings in Aleppo. Disparate casualty figures are common in the Syrian conflict, especially in the immediate aftermath of big attacks.

An activist group called the Local Coordination Committees said at least 25 died. The Britain-based Syrian Observatory for Human Rights said at least 27 died.

And an Aleppo-based activist, Ahmad al-Ahmad, said 47 were killed in all. He said 27 died in or near a crowded bus, while 10 others were killed as they waited to collect water from a public tanker, and 10 more died later as ambulances ferried scores of wounded to hospitals.

An amateur video posted by activists online showed paramedics helping a wounded man whose face was covered with blood come out of the bus, then rushing him way. The lifeless body of a woman is seen on a back seat of the bus, while one of a man lies on the pavement outside.

The footage also shows paramedics, flashlights on their helmets, pulling an older man from a bus window in the darkness. An unidentified man wails to the cameras, saying the bombs are "falling on us every day."

The video appeared genuine and corresponded to AP's reporting of the events depicted.