The Syrian government forces killed at least 100 rebels in the northern city of Aleppo, where intense battles have flared up over the past 24 hours, state-run news agency SANA reported on Friday.
The Syrian army killed the rebels during separate battles in several areas in Aleppo, said the report, adding that rebel vehicles were also destroyed.
Meanwhile, the Syrian Observatory for Human Rights (SOHR) said the rebels fired over 400 mortar shells into government-controlled areas in Aleppo over the past 24 hours, killing at least four people and wounding over 70 others.
The toll is likely to rise due to the high number of critically wounded people, SOHR added.
The Britain-based watchdog group, which relies on a network of activists on ground, said the most violent battles were taking place in the Jamiyet al-Zahra district and several areas in the old quarters of Aleppo.
So far, five rebel fighters were documented killed and others were wounded during the battles.
On Thursday, a total of 13 rebel groups, mainly the Al Qaeda-linked Nusra Front and other jihadi groups, declared the formation of a joint operations room to lead a wide-scale offensive against the government-controlled areas in Aleppo and its countryside, Xinhua news agency reported.
Aleppo, Syria's largest city and once an economic hub, has become carved out between the rebels and the Syrian troops.
The rebels attempted repeatedly to storm government areas in the hope of seizing control of the entire city of Aleppo without success.
