The Syrian army and rebels deployed more forces in and around Aleppo on Wednesday as a "decisive" battle for control of the country's second city raged, activists and regime sources said.
"Hundreds of rebels from all over the north of Syria are arriving in Aleppo, which appears to have become the decisive battle," a journalist for a Syrian newspaper working in the city told AFP.
"Around a dozen districts on the outskirts of the city are in the hands of the rebels and you can hear the sound of bombardment and automatic gunfire," he said.
Rami Abdel Rahman, director of the Syrian Observatory for Human Rights, confirmed the influx of rebel fighters.
They "are sending numerous fighters to Aleppo to battle the regime because, for them, Aleppo is as important as Benghazi was for the Libyan rebels."
"Aleppo is the capital of the north and the northern regions are already in their hands so, if this city falls, the regime is over and the two sides know it," he said.
Abdel Rahman said the army had also sent reinforcements to the city.
"In the past 48 hours, there are army reinforcements arriving on the Damascus-Aleppo highway," he said, adding that rebel forces were targeting the convoys.
On Wednesday afternoon, they used roadside bombs to hit a convoy of security forces travelling towards the city, killing eight. On Tuesday, the had attacked a convoy in a bid to slow its arrival in Aleppo.
"It's a decisive battle and the regime is sending reinforcements to stop the rebels from taking its bases and public buildings," he said.
A security source said the key battle underway was in the districts between the city and the airport, "which are in the hands of the terrorists."
Clashes continued in the neighbourhood of Bustan al-Qasr, in the south of the city, where army helicopter gunships fired on the neighbourhood, the Britain-based Observatory said.
In Aleppo, clashes raged in the central Al-Jamaliya neighbourhood, close to the local headquarters of the ruling Baath party. In Kalasseh, in the south of the city, rebels set fire to a police station, the Observatory said.
Fighter jets overflew the city, breaking the sound barrier but not carrying out bombing raids, Abdel Rahman told AFP.
Nationwide, the Observatory put the death toll at 45 by Wednesday afternoon, the majority civilians.
The watchdog also reported clashes in the district of Al-Hajar Al-Aswad in Damascus, one of the last remaining rebel bastions in the capital, 10 days after fighting broke out there.
Helicopter gunships and heavy machinegun fire pounded the embattled southern neighbourhood, as they tried to "reclaim" it, the Observatory said.
Elsewhere in the country, a bid by security forces to put down a mutiny at a Homs prison left "dead and wounded," and a rebel fighter was shot dead in the city's Al-Qarabis district, the Observatory said.
And in Hama province, 16 people were killed in an army assault on the village of Sharia along with a couple and their two children who were killed in Qalaat al-Madiq nearby as they tried to flee shelling in their village.
A video distributed by the Observatory showed grisly footage of the bodies of the family, shrapnel having torn open the faces of the children and ripping open the head of their father.
The group put the updated toll for violence across the country on Tuesday at 158 dead -- 114 civilians, 31 Syrian soldiers and 13 rebel fighters.