The University of Pittsburgh is setting up security check points at building entrances after a series of bomb threats have prompted evacuations of educational buildings and residence halls.

School officials say students and faculty will now need a school ID to get into buildings, which will also have security checkpoints set up to search bags. Non-residents will also not be permitted in dormitories.

If the school does receive more threats, university officials say they'll also limit access to buildings once they're cleared.

The university is also urging faculty to make arrangements for students to make up work missed because of evacuations.

The school has received more than 20 threats since February. Local, state and federal officials are investigating.

A $50,000 reward is being offered in the case.

Copyright 2012 The Associated Press.