"The Russian Federation have confirmed that we will have 11 hour per day … We are still unclear whether we will have four days from tomorrow, and can go until Monday but we hope so because we need experience in this very difficult situation … They have said 11 hours per day, four days from today, Thursday," Egeland told a briefing.
The official added that the United Nations had requested from Russia an extra day of humanitarian pauses earlier Thursday.
"Armed opposition groups say they will enable this to happen," Egeland added.
Egeland, who advises UN Special Envoy for Syria Staffan de Mistura, said UN agencies had been unable to proceed with evacuations of the sick and wounded from eastern Aleppo, pending permits from all sides of the conflict. Evacuations are expected to begin on Friday, he added.
Russian Defense Minister Sergei Shoigu announced on Tuesday that an eight-hour humanitarian pause in Syrian and Russian airstrikes in Aleppo would begin on Thursday. It was later prolonged to 11 hours at the request of the United Nations.
Heavy fighting has been continuing in and around Aleppo since Syrian government forces began a major offensive on the rebel-held eastern districts after the collapse of the ceasefire brokered by Russia and the United States in early September.
