Vernor Munoz Villalobos, special rapporteur on the right to education for the UN's Human Rights Council, said that this year so far there had been at least 172 such attacks against 60 in the whole of 2005.

The attacks "result in the loss of lives, destruction of already precarious infrastructures, and the closing down of schools" as well as depriving children "of their fundamental right to education," he declared.

"As a consequence, 200,000 to 500,000 children are denied the right to education in Afghanistan.....I am appalled that anyone would target children and their teachers," said Munoz, from Costa Rica, in a statement issued in Geneva.

Last week, the UN children's agency UNICEF also complained about assaults on schools -- widely practised in the 1980s by then Western-backed Islamic guerrillas fighting a Soviet-supported leftist government in Kabul.

But UNICEF avoided accusing any special group over the attacks, appealing only to "all parties" to stop them.

Independent reports say that in some incidents teachers have been killed in front of their pupils and that parents are warned by "night letters" distributed by insurgents to keep their children at home and teach them religion.

Munoz did not name the Taliban -- who effectively shut down education for girls and young women when they ruled Afghanistan from the mid-1990s until late 2001 -- but the wording of his statement left no doubt that they were his target.

He said the attacks were systematic in some parts of the country and were staged "by terrorist groups with the apparent aim of forcing parents to refrain from sending their children to school" and at forcing the government to close schools down.

Although both boys and girls schools appeared to be targeted indiscriminately, Munoz said, the attacks affected girls most because there were fewer schools for them and parents were especially reluctant to expose their daughters to danger.

Munoz called on the Afghan government and "forces on the ground" -- a clear reference to British-commanded NATO troops -- to step up efforts to endure the safety of students, teachers and all educational personnel.