Preparations for evacuation of besieged east Aleppo are under way following an attack on a medical convoy by pro-government forces. Russia, a close ally of Syrian President Bashar al-Assad, said the evacuation of 5,000 east Aleppo residents had begun. Jan Egeland, a UN humanitarian adviser, said he was hopeful about the evacuation but that Russia asked for UN involvement too late. The International Committee of the Red Cross said it had 100 volunteers and 10 ambulances waiting to enter the rebel-held territory. The evacuation of Aleppo's last rebel enclave would end more than five years of fighting for the city.