Syrian government forces have mounted assault on Aleppo, as rebels make gains in the countryside in the north.

Special envoy Kofi Annan has voiced his concern. And the Arab delegation at the UN has drafted a resolution to establish safe areas for civilians. Laurie Lew has the details.

It’s the battle for Aleppo.

Syrian government forces stepped up their operation, in a bid to dislodge the rebels and regain control of the northern city.

Rebel forces say they beat off the first wave of attacks that began on Saturday morning.

According to the Syrian Observatory for Human rights, at least 29 people were killed on Saturday.

Civilians crowded into basements seeking refuge from the bombing. Some describe the clashes as the fiercest since the unrest began.

Kofi Annan voiced concern over an "imminent battle" in Aleppo.

The international mediator cited reports of the concentration of troops and heavy weapons around the city.

He called for restraint and said it underlined the need for world powers to unite in pressing both sides to work for a political transition.

An Arab delegation at the UN has drafted a resolution to establish safe areas to protect civilians.

According to the Arab League, the proposals will now be discussed within the UN, and between members of the Security Council.

Earlier in Doha, the Arab League had called for the establishment of such areas.

The League has also called for the protection of humanitarian aid and the widespread adoption of economic and political sanctions.