Authorities in western Afghanistan are investigating whether 100 schoolboys who were hospitalised yesterday were poisoned, police said.

The boys, ages 10 to 14, fell sick after they ate beans from a vendor outside the school who told them the meal would help them pass their examinations in the western city of Herat, according to Abdul Jabar Rozi, Herat's police chief. The vendor was arrested later yesterday and an investigation launched into whether the food was deliberately tainted, he said. Taliban insurgents have poisoned Afghan police and army soldiers as part of their fight to topple the US.-backed government, but periodic reports of poison attacks on schools have mostly turned out to be the result of accidental food poisoning or mass hysteria.