Several schools in Florida, Pennsylvania, Ohio and Iowa have been placed on lockdown in the past 24 hours due to threats made or individuals with guns reportedly seen in the vicinity of the schools.

Students at some schools were told to sit on the floor and had to hide under their desks as the teachers turned off the lights. Students witnessed police entering classrooms with their guns drawn, local reports indicate. Panicked parents also rushed to pick up their children.

At Mater Lakes Academy High School in Miami-Dade, Fla., students hid under their desks and the teachers turned off the lights and locked the doors, according to Local10 news.

Police made the decision to place the school on lockdown late Wednesday afternoon after a student, already suspended for making threats against the school, made a threat to shoot up the school.

“Everyone started freaking out because they saw the cop cars. We already [had] locked the doors,” one girl said.

Students went on Twitter with the hashtag #mlalockdown to post pictures and also express their fear. One student wrote, “OML, I was so scared.”

No threat was found at Mater Lakes and students were released.

Several threats made to schools in Batavia, Ohio, are now under investigation by police after four schools were placed on lockdown Wednesday, reports local WLWT.

Amelia High School and Middle School were placed on lockdown after a threat was made to the school yesterday. Staff received a threat via email, saying within an hour people would be at the school to cause harm and that an explosive was planted.

Parents had to pick up their children at a nearby staging area at a church, which was secured by officers.

No violence occurred at the Amelia schools, but it was a harrowing experience for students and parents, who were in a traffic jam tried to get to their children.

Two schools nearby those schools, Glen Este High School and Middle School were also placed on lockdown shortly due to an anonymous threat.

In Davenport, Iowa two schools were also placed on lockdown when someone with was reportedly spotted with a rifle near Davenport West High School, according to local WQAD.com.

Nearby Wilson Elementary School was also placed on lockdown due to its proximity to the high school. The lockdown was lifted after police investigated.

In the Kensington section of Philadelphia a shooting across the street prompted the school to be placed on lockdown, according to local 6abc.com.