Syria withholds aid to 900,000, risks new siege in Aleppo: UN

Syria's government is refusing UN appeals to deliver aid to 905,000 people including in Aleppo, the city at the centre of an eruption of violence in the past two weeks, UN humanitarian advisor Jan Egeland said on Wednesday.

"We seem to be having new possible besieged areas on our watch, we are having hundreds of relief workers unable to move in Aleppo," he told reporters after a weekly humanitarian meeting of nations backing the Syria peace process.

"It is a disgrace to see while the population of Aleppo is bleeding their options to flee have never been more difficult than now."