United Nations Secretary-General Ban Ki-moon on Friday demanded that the Syrian government state that it would not use chemical weapons "under any circumstances," according to Reuters.
He said, "I remain deeply concerned about the reports of the possible use of chemical weapons," citing a report in which Syria said it would use weapons against foreign attackers.
"I demand... that the Syrian authorities categorically state that they will not use chemical or other weapons of mass destruction under any circumstances," he said, during a joint press conference with British Foreign Secretary William Hague in London ahead of the Olympic games.
Ban Ki-moon also said, "I urge the Syrian government to halt the offensive," according to British newspaper The Independent.
More from GlobalPost: Syria: UN and US fear massacre in Aleppo
British Foreign Secretary Hague, addressing concerns over reports of vicious fighting in Aleppo, said, "This utterly unacceptable escalation of the conflict could lead to a devastating loss of civilian life and a humanitarian disaster."
The former head of the UN observer mission in Syria said on Friday that it is "only a matter of time" before Syrian President Bashar al-Assad's government falls, according to the BBC.
"In my opinion it is only a matter of time before a regime that is using such heavy military power and disproportional violence against the civilian population is going to fall," said Norwegian Maj. Gen. Robert Mood. But Assad's fall will not necessarily end the conflict in Syria, he added.
The news comes as both rebels and the government prepare for what the pro-government al-Watan newspaper called the "mother of all battles," the BBC said.
Both the UN and the White House have expressed fears that there could be a massacre in Aleppo at the hands of Syrian government forces.
More from GlobalPost: White House warns of massacre plans for Syria's Aleppo