The United Kingdom, France and the United States have requested an urgent UN Security Council meeting on the escalating campaign in Syria's second city of Aleppo, diplomats said.

The meeting was likely to be held at 10 am (1400 GMT) on Sunday, the diplomats said. Intense air strikes toppled buildings and killed at least 45 civilians in Aleppo on Saturday. 

UN Secretary General Ban Ki-moon said he was appalled by the "chilling" upsurge in fighting in Aleppo and warned that the use of advanced weaponry in the battleground city could amount to war crimes.

Ban cited reports of air strikes involving the use of incendiary weapons, bunker buster bombs and other powerful munitions in the offensive launched by the Syrian army two days ago to recapture the city.

He warned that "the apparent systematic use of these types of indiscriminate weapons in densely populated areas may amount to war crimes," a statement from his spokesman said. 

Source : XINHUA