Up to 16,000 people were displaced in Syria's Aleppo by intense attacks on the rebel-held eastern part of the city, UN humanitarian chief and relief coordinator Stephen O'Brien said on Tuesday.
The area had no functioning hospitals, food stocks were nearly exhausted and it was likely that thousands of more people would flee from their homes if the fighting keeps on going in the coming days.
"The situation is very bad. There's intense fear of collective annihilation," said Abu al-Abbas, a medic who lives in the area.
"This week I've changed locations three times," he added, speaking on Monday using a social networking site.
"In the shelter, we had dead people that we couldn't take out because the bombardment was so intense."
Aleppo hosted the most pressing battle in Syria's war, pitting President Bashar Al-Assad. The Syrian government was backed by countries such as Russia, Iran, etc against mostly Sunni groups including some supported by the US, and Turkey.
Russian President Vladimir Putin ordered mobile field hospitals be sent to Aleppo to provide medical assistance to residents. In addition, Russia has been the Syrian regime's closest and most powerful ally. Its support has been widely blamed by the destruction of hospitals and schools across the country.
The fighting escalated after the army began a new offensive last week, bringing more eastern Aleppo districts close to the front line as rescue and ambulance workers said their vehicles and equipment are running out of fuel.
According to Syrian national newspaper SANA, eight people were killed on Wednesday and seven others were injured in rocket shells fired by the terrorist organizations on a number of residential neighborhoods in Aleppo.
The Syrian Observatory for Human Rights, a Britain-based war monitor, said warplanes pounded eastern Aleppo districts overnight, killing at least 18 people, including 12 in al-Shaar district near the new front line.