PESHAWAR, Nov 26: A powerful bomb exploded in the Government Girls Primary School in the village of Sher Bahadur near here on Monday morning, destroying the main gate, windows, doors and boundary wall of the school.

The school administration is reported to have received anonymous letters a few days ago, with a threat if its students did not observe purdah, the building of the school would be destroyed.

Police officials told Dawn they had increased patrolling and tightened security, particularly in areas where terrorists and extremists had intensified their activities.