The international community has stepped up the pressure on the Syrian government to end its assault on the country's biggest city, Aleppo.
Western nations have warned of a potential massacre as military forces press home their attack.
The pro-government al-Watan newspaper warned that the "mother of all battles" was about to start.
Activists said people were already dying in military assaults, as forces continued to build up around the city.
UN Secretary General Ban Ki-moon urged the Syrian government to halt its offensive. He also demanded a clear statement that it would not use chemical weapons under any circumstances
"The violence from both sides must stop for the sake of the suffering civilians of Syria," he said in London.
'Disaster' warning
UK Foreign Secretary William Hague said the people of Aleppo were threatened with a potential massacre.
"This utterly unacceptable escalation of the conflict could lead to a devastating loss of civilian life and a humanitarian disaster," he said.
He urged all permanent members of the UN Security Council - including Russia and China, who have vetoed three resolutions - to condemn the actions.
Separately, UN High Commissioner for Human Rights Navi Pillay appealed to both sides to spare civilians, citing concerns of "the likelihood of an imminent major confrontation".
The BBC's Wyre Davies, on the Syria-Turkey border, says conditions in Aleppo are reported to be dire.
Thousands of government troops have been drafted in from other areas and are encircling the city, he says.