Security forces raided the seminary in Quetta and found that 100 students from Afghanistan were illegally studying and staying there, an official said.
The students have been booked under the foreigners act as they did not have the required documents to stay in Quetta or study at the seminary which was sealed, he said.
Balochistan Home Minister Mir Sarfaraz Bugti said authorities were taking steps to identify the illegal aliens in the wake of the suicide bomb attack at a civil hospital in Quetta in which nearly 70 people, mostly lawyers, were killed earlier this month.
Illegal Afghan nationals cross over to Pakistan regularly through the Chaman border post which was closed last week after Afghan protesters celebrating their national day pelted stones at the friendship gate checkpost and burnt a Pakistani flag.
Yesterday, security forces arrested six terrorists from Noshki area in Balochistan province.