BEIRUT (AFP) - A Syrian regime air strike hit a school in the main northern city of Aleppo on Sunday killing five children and four other civilians, a monitoring group said.

"Military aircraft struck a school in east Aleppo city and killed five children, three female teachers and one man," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.

He said a number of people were seriously wounded and the death toll was likely to rise.

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

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

Many schools in Aleppo city have been forced to close, while others hold classes in basements.