A new U.N. report says hundreds of millions of children are excluded from essential services and denied protection around the world, leaving them open to exploitation and discrimination.

The findings of the United Nations Children's Fund make for grim reading.

More than 50 million child births go unregistered each year, exposing those children to denial of access to essential services such as education and health care. One in every 13 children in developing countries are orphans. The AIDS epidemic alone has orphaned 15 million children.

About 250,000 youngsters are serving as child soldiers in conflicts around the world, and an estimated 171 million children are working in hazardous jobs around dangerous machinery, in mines or on farms.

UNICEF Executive Director Ann Veneman says societies tend to ignore these children. "They are the world's most vulnerable children, trapped in circumstances that push them to the margins and shadows of society," she said. "They are children who are not registered at birth and grow up without an identity. They are the children who suffer the death of one or both parents. They are children who are forced into adult roles when they should be at school or at play. "

Appearing with Ms. Veneman at a London news conference was Corina Panaite, a 20-year-old Romanian woman who told a tale of the sexual exploitation of children that is going on in Europe.

Ms. Panaite says that when she was 17, a friend enticed her to travel to Ireland to work in a restaurant. But when they arrived, after traveling on false passports, they were taken to an apartment and forced to work as prostitutes.

Ms. Panaite hopes other girls learn from her example. "When I left home, my dream was to have a better life abroad," she said. "Now I realize my future is in my country. I have a message for all the girls who have dreams like me: Please be more careful when somebody helps you to go abroad and promises you a faster way to achieve your dreams."

The UNICEF chief, Ms. Veneman, says the agency hopes to raise public awareness of what is happening to exploited children, which could lead to more pressure on governments to act.

She said many of the issues, such as combating child trafficking, will require stricter law enforcement and regional cooperation.