The Syrian government resumed its attack at Aleppo on Tuesday, after the U.S. stopped its negotiations with Russia in an attempt to restore the ceasefire in the region.

The United Nation has already called on to stop the dreadful violence that occurred in the Aleppo, which was being reeled from some of the most brutal fights in the last five years.

The Syrian army said Russian-backed military advances forward to gain control of the eastern half of Aleppo, a rebel-occupied area two weeks ago.

Some high-rise buildings in the center of Aleppo were captured by loyalist fighters thrusting towards other enemy districts.

Government forces is slowly advancing after street fights on the front line broke, according to Syrian Observatory for Human Rights, a pro- opposition monitor.

Rami Abdel- Rahman, head of the Observatory told the AFP that the government forces are focusing on the tall buildings where they can observe entire streets and neighborhood from there.

Bombardment noise could be heard all night from the southern end of the city, which only turned quieter during dawn, an AFP correspondent reported.

Syrian State News Agency reported that six people died on Tuesday after the bombardment of the rebels to the government- controlled west, including Aleppo University campus.

On Monday also Russian embassy was hit by a mortar leaving damage but without casualties, Russian Ministry said.

Since the battle began in March 2011, over 300,000 deaths were recorded as the attempt to establish a diplomatic solution occasionally failed.

U.S. and Russia are backing up both sides, blaming each other for the failure. 

Washington announced on Monday that agreement between the two opposing sides on ceasefire is suspended. America accused Russia on encouraging Syrian government to advance the attack.

Russia on the other hand blamed America for failure in convincing the rebels to distance themselves from extremist fighters.

Russia and America mutually agreed for an open communication channel to ensure that their separate campaigns on bombing would not get in each other's way.