Twelve civilians were killed Saturday in air strikes on a rebel-held neighbourhood in Aleppo, the local civil defence told AFP, in the second day of bombardment on Syria's former economic hub.

Government bombardment on the flashpoint rebel town of Douma east of Damascus killed 13 people, according to the Syrian Observatory for Human Rights.

The barrage of air strikes on Aleppo began around 10:00am (0700 GMT) on several neighbourhoods, including the heavily-populated Bustan al-Qasr district, an AFP correspondent in the city said.

But the deadliest raid was on the Tareeq al-Bab neighbourhood on the eastern edges of the city.

A civil defence member responding to the incident said 12 civilians had been killed there.

AFP footage showed a civil defence volunteer carrying a screaming woman down a ladder from a damaged building in the neighbourhood, as a pick-up truck drove the remains of one person away.

Another volunteer brought down a young man cradling a baby from a high floor in a crane.

At least nine other civilians were wounded in air strikes on other parts of the city, including Bustan al-Qasr and Al-Mashad, the civil defence member said.

It was the second day of deadly strikes on Aleppo, where a fragile truce had brought weeks of relative calm.

On Friday, 25 civilians were killed and another 40 wounded in regime air strikes on rebel-controlled parts of Aleppo.

Once Syria's commercial hub, the northern metropolis has been divided by government control in the west and opposition groups in the east.

A ceasefire deal brokered by Russia and the United States saw Syria's government and non-jihadist opposition agree to halt attacks while pursuing peace talks.

Violence dropped across the country, including in Aleppo city, where residents cautiously began shopping in open-air markets and taking their children to parks.

But a surge in violence in recent weeks has left the ceasefire all but collapsed.

In the rebel-held town of Douma, 13 people -- including three women and two children -- were killed in government shelling on the city.

Douma lies in the Eastern Ghouta opposition bastion, where the Jaish al-Islam rebel group -- also party to the truce deal -- is dominant.

More than 270,000 people have been killed since Syria's conflict first broke out in 2011.