The Syrian army has attempted to wrest back control of Aleppo as rebels are reported to be withdrawing from their positions.
The army claims it has seized the Salaheddin district from rebel forces, but however human rights organisations have claimed that fighting is still ongoing.
"Fighting is still raging in the district of Salaheddin and there are initial reports of many dead. It is impossible to document the casualties because of the ferocity of the clashes," said the director of the Syrian Observatory for Human Rights Observatory, Rami Abdel Rahman.
Colonel Abdel Jabbar al-Oqaidi of the rebel Free Syrian Army (FAS) also denied the reports.
"It is not true the regime army has seized control of the district,"
"It is true that there is a barbaric and savage attack. They are using all the weapons at their disposal to attack Salaheddin, including fighter jets, tanks and mortars."
Amnesty International has warned of an increased use of heavy weapons.
Sattelite images release by AI on Wednesday show over 600 craters, some near residential areas, probably caused by artillery fire.
"Amnesty International is sending a clear message to both sides in the fighting: Any attacks against civilians will be clearly documented so that those responsible can be held accountable," said Christoph Koettl, emergency response manager for Amnesty International USA.
