Officials allege school has links with al-Qaida and other militant groups.
Charges deepen the fall of a once-powerful figure who planned political comeback.
Militants have so far rejected the prospect of negotiations.
No group has claimed responsibility but separatists are suspected.
Latest in a series of allegations by both sides over the past week.
15 also wounded in the mosque attack on a former provincial minister.
A government official says a bomb planted outside a shopping center in southwestern Pakistan has killed a 13-year-old girl and wounded over 20 people.
Motive for attack unclear but suspicion may fall on separatists.
Heavy rains that caused flash floods and collapsed houses in different parts of Pakistan have also displaced more than 80,000 over the past four days.
Karachi suffering due to inadequate drain system.
