The international children's agency, UNICEF, has said that hundreds of millions of children are being abused and exploited but they have become virtually invisible to the world.
Its annual report says that more than half the children in most developing countries are not registered at birth and governments often do not take their needs into account.
UNICEF's Executive Director Anne Venemen said the lack of an official identity makes children vulnerable.
UNICEF hopes to reduce the mortality rate among children under five years of age by two-thirds, ensure primary schooling for all boys and girls, and halt the spread of AIDS and incidences of malaria.
