REBEL FIGHTERS IN Syria have launched a military offensive to “liberate” the country’s largest city as an activist group reveals that 2,750 people have been killed in the conflict this month.

That figure from the British-based Syrian Observatory for Human Rights brings the death toll to more than 19,000 since unrest began 16 months ago.

June had been the deadliest month so far but violent clashes between opposition fighters and forces loyal to President Bashar Assad continued to escalate this month.

According to Observatory chief Rami Abdul-Rahman, 2,752 people – 1,933 civilians, 738 government troops and 81 rebels – were killed in the first 21 days of July.

BBC News reports fierce fighting in both Damascus and Aleppo this morning. Meanwhile, AFP says that rebel forces have occupied a second border post with Turkey but the Syrian army claims it has retaken another crossing along the northern frontier with Iraq.

In the capital, Assad’s army has deployed helicopters and the “feared Fourth Brigade” to pound the northeastern suburb of Barzeh.

“Troops have stormed the northwestern Barzeh district of Damascus with tanks and armed personnel carriers,” the Observatory said, noting snipers from the elite unit had been spotted on rooftops.

“Two helicopters are pounding the Barzeh district, and towers of smoke are rising above the neighbourhood,” Rahman told AFP. “The deployment in Barzeh is very heavy.”

Troops have also been sent to the western suburb of Mezzah.

State television is showing footage of soldiers commanding areas of Qaboun in the capital, the site of a series of attacks involving heavy artillery, tanks and helicopters. SANA TV also broadcast images of dead bodies, claiming them to be those of “terrorists”, the regime’s term for rebel fighters.

In Aleppo, Reuters reports battles near the main intelligence base after demonstrators defaced a statue of President Assad’s father, the late leader Hafez.

“Sounds of explosions from different areas are shaking the whole city. A heavy exchange of gunfire has been going on near the State Security Headquarters in al-Mouhafaza (district) since the morning,” a housewife there said during a telephone conversation.

Yesterday, UN chief Ban Ki-moon said he was “deeply distressed by the rising death toll,” and he warned that the limited extension of the UN mission showed “the onus is above all on the parties, with the Syrian government in the first place, who must stop the killings.”

It is not possible to independently verify death tolls or territorial claims as there is limited access for foreign journalists to Syria.