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DENVER (AP) — Threats made against schools across the country that led to evacuations on Monday could be the latest example of so-called "swatting" against schools.

A bomb threat at Ben Franklin Elementary School in Rochester results in students being sent to nearby Mayo High School on Monday until police said it was safe to return. Assistant Superintendent Brenda Lewis said the threat came in just before noon as an automated recording, received on the main office phone.

Forest Lake Elementary school in the city of Forest Lake was also evacuated after a bomb threat call around 12:15 p.m. School district spokeswoman Renee Reedy says police and firefighters searched the school but found nothing. Students were taken to another nearby elementary school and bused home from there.

In recent months, hoaxers playing online games have allegedly used proxy servers and other high-tech identity-disguising tools to anonymously threaten schools online or in phone messages with electronic voices to trigger a huge police response, including SWAT teams.

The latest threats led to the evacuation of schools in Colorado, Delaware, Minnesota, New Hampshire and Wisconsin. Media outlets in the United Kingdom also reported evacuations.Valley High School and Altoona Elementary School in the Des Moines area and Excelsior Middle School in Marion and Tate High School in Iowa City received calls and were also evacuated Monday.

Some officials described Monday's threats as automated, and the ones made in Colorado and Minnesota were received just before noon local time.