Schools in several states were evacuated or put on lockdown after multiple departments received 911 calls reporting active shooters. In Pennsylvania, police across the state responded to numerous schools after receiving the calls.

The Pennsylvania State Police believe the calls are computer-generated "swatting calls" but are still treating them like real emergencies.

"County 9-1-1 has received three separate calls reporting that there is an active shooter in three separate schools. We are also aware that similar reports are coming in for schools outside of the county. In each instance, law enforcement is responding but believes that these are false reports. Thus far, there has been no active shooter found and no injuries at any school. Law enforcement will continue to thoroughly check out any reports," an Allegheny County spokesperson told WTAE.

Yesterday, over two dozen schools in Massachusetts and Rhode Island were targeted by hoax calls.

The hoax calls come days after a 28-year-old former student killed six people at The Covenant school in Nashville, Tennessee. Three nine-year-old children and three adults were killed. The shooter was also killed by responding officers on the second floor of the school.

Investigators are still trying to determine a motive for the shooting.