GENEVA - Suicide bombings, attacks on schools and roadside bombs have put the lives of scores of young Afghans at increasing risk, and threaten to undercut important gains in girls' education, UNICEF said on Thursday.

Increasingly bloody fighting between Taliban insurgents and Afghan and Western forces created a dilemma for many parents who worried about letting their children go to school, the U.N. agency said in a Child Alert report.

"Girls are particularly affected by the insurgents' targeting of girls' schools and even of the pupils themselves," the report concluded.

The Taliban banned girls from education during their rule and have attacked hundreds of schools and killed some teachers and pupils as part their war against the government and its Western backers.

The report said at least 1 million Afghan girls of school age -- 35 percent of the total -- were not enrolled. Literacy is as low as 2 percent in some rural areas.

Martin Bell, a former BBC journalist who serves as UNICEF humanitarian emergencies ambassador, said the advances in Afghanistan's education and health systems in the years since U.S.-led forces ousted the Taliban were very fragile.

"So much progress has been made since 2001, in those six years, and now some of it is being turned back with attacks on the schools, with children not going to school. The situation is absolutely critical," he told Reuters Television in Geneva.

"The nightmare situation is that a whole generation of girls will grow up illiterate. And then who will teach the future generations?" Bell said.

Bell said many children were killed by attacks meant for other targets, primarily the NATO-led international forces seeking to support the Afghan government.

Twelve children died in a suicide attack on an international military convoy near a Uruzgan province playground in June, and in March one child died in an attack on U.S. forces in Kabul and four were killed in Kandahar attacks aimed at Canadian troops.

Air strikes during a two-day battle in Helmand province in June caused 27 civilian deaths, including 17 children, the report said.

It also noted a "disturbing" use of children as combatants -- both child soldiers and suicide bombers -- by the Taliban.

While there are not thought to be many underage fighters at present, UNICEF said increasing numbers may be attracted to the Taliban which offers better pay than joining the Afghan army.

"When the security situation deteriorates, there is a real danger that young people -- vulnerable and unable to use their new skills in the marketplace -- will again be recruited into armed groups that can offer them protection," the report said.