Rebels halt Syrian army’s assault on Aleppo

Syrian rebels have held off an offensive by regime forces in Aleppo, with the head of the main opposition bloc calling for heavy weapons and saying President Bashar al-Assad should be tried for "massacres".

After massing for two days, troops backed by tanks and helicopter gunships moved on southwestern Aleppo on Saturday where rebels concentrated their forces when they seized much of the northern city on 20 July. The fighting continued into Sunday morning with opposition officials reporting that rebels had successfully fended off the first wave of the attack.

At least 29 people were killed on Saturday, the Syrian Observatory for Human Rights said, contributing to a figure of around 140 deaths reported nationwide. There is growing concern about the risks of reprisals against civilians in the country's commercial capital.

The London-based watchdog said more than 20,000 people, mostly civilians, have now died since the uprising against Assad's government erupted in March 2011.

Civilians crowded into basements seeking refuge from the bombing, with the Observatory's Rami Abdel Rahman describing the clashes as the "fiercest" of the uprising.

UN-African Union envoy Kofi Annan said on Saturday he was "concerned" about reports of the concentration of troops and heavy weapons around Aleppo "in anticipation of an imminent battle".

"The escalation of the military build-up... is further evidence of the need for the international community to come together to persuade the parties that only a political transition, leading to a political settlement, will resolve this crisis," he said.

Activists said Syrian tanks moved in on south-western districts of Aleppo city early on Saturday.

Rebel-held areas were bombarded throughout the day, with military aircraft flying over at low altitudes, they said.

Violent clashes were reported around the Salah al-Din and Hamdanieh quarters near the centre.

However, by the end of the day it appeared that the rebels had largely held their ground.

They are believed to control between a third and a half of all neighbourhoods in the city of three million people, especially a cluster in the north-east around Sakhour and other areas in the south-west.

Colonel Abdel Jabbar al-Oqaidi of the rebel Free Syrian Army said his forces had repulsed troops in Salaheddin district and that the regime offensive had been stopped.

"We managed to force the army to the neighbourhood of Hamdaniyeh," he told AFP news agency on the phone, adding that while the army had been halted on the ground, artillery and gunships continued to pound the city.

Abdel Rahman said the fact the soldiers had been stopped in Salaheddin "does not necessarily mean a withdrawal as their strategy is to bombard ... to cause an exodus then launch an assault even more fierce".

An AFP correspondent said rebels were poised to launch a final raid on a strategic police post in the city centre, where 100 men armed with Kalashnikovs have been holding out for three days.

Its capture would open a corridor between Salaheddin and the rebel-held district of Sakhur, some 6km to the northeast.