More than a billion children, or over half the global population of minors, are now estimated to live in urban areas, according to UNICEF, which is releasing the report entitled "The State of the World"s Children 2012" on Tuesday.
Not all children living in urban areas are benefiting from the economic expansion in cities, UNICEF said in a statement issued ahead of the report"s release.
"In this increasingly urban world, the absence of a sustained focus on child rights means that some children are being left behind," the statement noted.
The report documents the struggles that urban children face in upholding their rights to survival, health, nutrition, education and protection.
"Although cities and towns generally offer better options for schooling, medical care and recreation, those already disadvantaged " including children living in slums and informal settlements, migrant children, or children living or working on the streets " are unlikely to enjoy the benefits," the statement said.
One of the report"s editors, Abid Aslam, said it was disturbing that so many children worldwide were being born into "extremely harsh" urban conditions, especially in slums, where homelessness, exploitative labour and gang violence are common.
"They don"t know often from one week to the next where they"re going to live, much less whether they"re going to be able to go to school, or whether they"re going to have clean, piped water," he said.