Beirut: The Syrian army launched a threatened counter-offensive against rebels in Aleppo Saturday, pouring troops into the southwest of the commercial hub, a human rights group said.
The reinforcements, which have been massing over the past two days, "have moved on the Salaheddin district, where the largest number of rebel fighters are based," the Syrian Observatory for Human Rights said.
"The fiercest clashes of the uprising are taking place in several neighbourhoods of the city," the head of the Britain-based watchdog, Rami Abdel Rahman, said.
"You can say that the fightback has begun."
Activist group the General Comittee of the Syrian Revolution said that troops were raking Salaheddin with heavy machinegun fire as they advanced on the neighbourhood, which has been a stronghold of rebel fighters since they seized large parts of Syria's second city on July 20.
Columns of troops backed by tanks and helicopter gunships have poured into Aleppo prompting concern among Western governments about the dangers of reprisals against the city's civilian population.