Syrian opposition fighters on Friday (October 28th) launched a major assault on regime forces to break a month-long siege of opposition-held neighbourhoods of Aleppo, AFP reported.

Opposition groups, including the Ahrar al-Sham coalition, fired waves of rockets into regime-held western Aleppo, killing at least 15 civilians, the Syrian Observatory for Human Rights said.

The Observatory reported fierce clashes on multiple fronts on the western and southern outskirts of western Aleppo, with three suicide car bombs targeting a checkpoint in the Dahiyet al-Assad neighbourhood. It had no immediate toll in the clashes or bomb attack.

Opposition fighters also targeted regime positions east of Aleppo city and in the coastal province of Latakia, including the Hmeimim military base.

Opposition groups "announce the start of the battle to break the siege of Aleppo", said Abu Yusef Muhajir, a military commander and spokesman for Ahrar al-Sham.

The Observatory said opposition forces also had fired dozens of rockets at the Nairab military airport and Aleppo international airport, and had fired rockets from Idlib province into the regime stronghold of Latakia, killing one person and wounding six.

Meanwhile, UN Secretary-General Ban Ki-moon has called for an immediate investigation into the Wednesday attack on a school in opposition-held Idlib that killed 22 children , his spokesman said Thursday.

"If deliberate, this attack may amount to a war crime," Ban said in a statement.