An estimated 40,000 children are trapped in extremely dangerous conditions in Raqqa as fighting intensifies in and around the Syrian city, the United Nations Children's Fund (Unicef) said, warning that "many are caught in the crossfire.""Heavy violence in the city of Raqqa is threatening the lives of children," said Geert Cappelaere, Unicef's Regional Director in the Middle East and North Africa Region.Cappelaere said on Friday that hospitals and schools were under attack and that those attempting to flee were in danger of getting killed or injured. He emphasised that children were being deprived of the most basic and life-saving necessities and that little aid had reached Raqqa since 2013 due to violence and access restrictions.Cappelaere added that the conflict had resulted in massive displacements in and around the city, with some 80,000 children from Raqqa city now internally displaced and living in temporary shelters and camps.Unicef called on all parties to protect children inside Raqqa, provide safe passage to those wishing to leave the city and grant a protected environment to civilians who fled the city.