At least 10 people including four teachers have been killed and 30 wounded after the Syrian army dropped a vacuum bomb on an elementary school in the northern city of Aleppo, Syrian Civil Defence sources have said.

"Ten people including teachers and students were killed when the Syrian regime bombed the Said al-Ansari school in the opposition-held Al-Ansari district," a member of the Syrian Civil Defence, who declined to be named, told Anadolu Agency on Sunday. The opposition Syrian National Council confirmed the incident as did the Syrian Observatory for Human Rights, a UK-based watchdog.

The observatory's chief Rami Abdel Rahman said that a large number of vehicles caught fire following the bombardment, adding that residents in opposition-held areas of Aleppo had been warned "against going out" due to the ongoing airstrikes by the Syrian government. Many schools in Aleppo city have been forced to close, while others hold classes in basements.

Another child was killed in a seperate air strike on a rebel-held neighbourhood of east Aleppo, the Britain-based Observatory reported.

Civilians targeted

The strikes come a day after government forces and rebel fighters exchanged fire in the northern city, killing at least 35 civilians.

"Seventeen other civilians were killed when rebel groups fired rockets on neighbourhoods controlled by the regime, including Suleimaniyah and other areas," the Britain-based group said.

Syria's civil conflict, which has entered its fifth year, has left tens of thousands of people dead and millions of others displaced both internally and externally.

Pictures circulating on social media depicted significant damage.

Fighting erupted in Aleppo in 2012, reducing swathes of Syria's commercial hub to ruins.

Government forces control the west of the city and frequently bomb rebel-held neighbourhoods in the east from the air.

The rebels often retaliate with rocket and mortar fire into government-held neighbourhoods.

Both sides have been criticised by human rights groups for firing indiscriminately on civilians.