Bangkok Post

July 20: Heavy fighting erupts in Aleppo, which had so far been largely spared violence during the uprising against Syrian President Bashar al-Assad which erupted on March 15, 2011.

July 23: Rebels say they have ``liberated'' multiple neighbourhoods, including Salaheddin in the south, on the road to Damascus.

July 28: The military launches a dawn assault, using helicopter gunships, artillery and tanks as well as ground troops. On July 29, rebels say they have held off the offensive.

July 30: Rebels seize a strategic checkpoint northwest of Aleppo, securing free movement between the city and Turkey.

August 8: Backed by tanks, regime forces launch a ground assault and enter Salaheddin.

August 9: Rebels say they have ``staged a tactical withdrawal'' from Salaheddin.

August 13: Fighting in Salaheddin, which is controlled by regime forces but where there are still pockets of resistance. The army advances into Saif al-Dawla, a second rebel-held area of Aleppo.

August 15: A Syrian air strike on a rebel bastion in the town of Aazaz flattens a string of houses and kills more than 40 people. Ground and air attacks on the district of Ouwayja northeast of Aleppo.

August 18: Helicopters drop leaflets over Aleppo urging residents not to shelter rebels and warning the rebel Free Syrian Army it has one last chance to surrender. Two hours later, helicopters fire on several central neighbourhoods.

August 20: The Syrian Observatory for Human Rights says troops backed by helicopters pound several Aleppo districts including Salaheddin, Suleyman al-Halabi, Shaar, Izaa, Saif al-Dawla, Tariq al-Bab and Bustan al-Qasr.