More than 100 unaccompanied children in eastern Aleppo are reported to be trapped under a building that is under heavy attack.
The UN children's agency warned of "alarming" reports from a doctor in the city that many youngsters who had been separated from their families were trapped in the building in the east of the city.
Regional director of UNICEF, Geert Cappelaere, said in a statement: “According to alarming reports from a doctor in the city, many children, possibly more than 100, unaccompanied or separated from their families, are trapped in a building, under heavy attack in east Aleppo.”
Mr Cappelaere did not give further details on the doctor or the location of the children but he said it was “time for the world to stand up for the children of Aleppo and bring their living nightmare to an end”.
He added: "We urge all parties to the conflict to allow the safe and immediate evacuation of all children. Unaccompanied and separated children have the right to be registered by a neutral humanitarian organisation and be reunified with their families – wherever they may be.
“Unicef is deeply concerned by reports of extra judicial killings of civilians including children and reminds all parties of their responsibilities under international law."
The comments came as pro-government forces continued their assault on Aleppo's few remaining rebel-held areas, trapping thousands of civilians.
Militia forces loyal to Syrian President Bashar al-Assad are reported to have entered homes and killed at least 82 civilians during their advance on rebel-held territory.
The Syrian military has denied the claims, calling them a “desperate attempt” to garner international sympathy. The army will declare control of the whole of Aleppo “at any moment”, Syrian state television said on Tuesday.
Aid workers and activists in the east of the city meanwhile pleaded for the international community to save them from what they said are arbitrary executions of non-combatants by Syrian government forces as the regime finally closes in on the rebel-held areas.
Between 50,000 and 100,000 civilians are still thought to be trapped by fighting in the rebel enclave, which is now as small as 2.5 square miles (four square kilometres).
Downing Street has described reports from Aleppo that Syrian regime forces have executed scores of civilians in the bombarded city as “extremely concerning”.
