Young people around the world should be given more of a say in decisions that affect their lives, according to a new report by the UN children's agency Unicef.

Taking children's views into account could lead to fresh and innovative ideas for fighting the spread of HIV, improving education and even diminishing the threat of future acts of terror, the UN Children's Fund says.

State of the World's Children

150 million - malnourished 120 million - don't go to school 180 million - in child labour

Unicef's annual report - based on three-year surveys of 40,000 children on four continents - suggests that many young people feel disconnected from political institutions, but could learn to be more active citizens through participation.

When children are excluded from decisions, they fail to develop vital skills - including the ability to express themselves, negotiate differences or assume responsibility.

"We would argue that the failure to have dealt positively with kids at some point in time just leads to terrorism later," Unicef's executive director Carol Bellamy said.

The report says the world is now a grim place for millions of its two billion children.

Wars have claimed more than two million children�s' lives since 1990, and every day 6,000 youngsters are infected with the HIV virus.

Developing vital skills

However there was praise for some initiatives in Latin American countries to include children in government programmes.

Mexico was praised for commitment to children's rights

"Latin America has shown outstanding leadership when it comes to listening to and respecting the views of children," Ms Bellamy said at the official presentation of the report in Mexico City.

She was joined by Mexico's President Vicente Fox, whose country was praised in particular for commitment to children's rights.

The Unicef report also praises Brazil for its example of enabling child participation in adult decision-making through a media centre called Casa Grande.

It also cites the role of an organisation called the National Movement of Street Boys and Girls - set up by adults in the mid-1980s - that contributed to drafting the 1988 Brazilian constitution and the country's law on children's rights.

Examples of how children brought about positive change are also given.

In the Pakistani province of Baluchistan - with a female literacy rate of 2% - boy scout troupes began lobbying local officials to let girls attend their schools, leading to 2,500 girls being enrolled in one year.