Students were evacuated and authorities were investigating after at least 10 Massachusetts schools received bomb threats on Monday morning.

Massachusetts State Police, local police and bomb teams were investigating a series of threatening calls, some of which were robocalls, received by schools in the state, WCVB reported.

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Officials confirmed that bomb threats were received in Ayer, Billerica, Brighton, Brookline, Charlestown, Hopkinton, Hudson, Leominster, Marlborough, Medway, Stoneham, Tewksbury, Boston Catholic High School and Cambridge Rindge and Latin School, WCVB added.

"Communities are following the established protocols that we have been training on across the state to assess each threat and the appropriate local response," a statement from the State Fire Marshal’s Office was quoted by WHDH. "The MSP Bomb Squad is responding to certain communities where appropriate."

Charlestown and Brighton high schools were put into safe mode while police investigated, meaning students were not allowed to move around the building, according to WHDH.

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Officials in Marlborough said the high school was evacuated as a precaution, WCVB added, also stating that Somerville City Hall received a similar phone threat.