Syrian regime forces and opposition factions sent hundreds of reinforcements to Aleppo on Monday (August 8th) as opposition fighters announced an all-out offensive to take the city, AFP reported.

The battle is intensifying after an opposition advance at the weekend broke through a three-week regime siege of the city's opposition-held east, dealing a major setback to regime troops.

Opposition forces on Sunday announced a bid to capture all of Aleppo city, but pro-regime forces are putting up a fierce fight and have begun pouring reinforcements into the city.

The Syrian Observatory for Human Rights said some 2,000 pro-regime fighters from Syria, Iraq, Iran and Lebanon's Hizbullah had arrived in Aleppo since late Sunday.

"Both sides are amassing their fighters in preparation for the great battle of Aleppo," said Observatory head Rami Abdel Rahman.

In a bid to break the siege, a coalition of opposition fighters overran a series of buildings in a military academy on the southwestern edges of Aleppo on Saturday and then pushed northeast to link up with opposition groups inside the city.

Abdel Rahman said Monday that hundreds of opposition fighters had arrived in Aleppo from the surrounding province and neighbouring Idlib.

Most were from Fateh al-Sham Front, the group that leads the opposition's Army of Conquest, he said, which changed its name from al-Nusra Front last month after breaking with al-Qaeda.