Several Massachusetts schools received bomb threats Tuesday, the third time in less than a week the region’s schools were targeted with threats.

Arlington High School and Groton Middle School were evacuated Tuesday after separate threats, FOX25 reported. Arlington students were initially told to shelter in place; however, students were ultimately dismissed just after 10 a.m. The threat is not thought to be credible, Arlington police said.

Plymouth South Middle School, Taunton public schools and Newton North High School received threats on Monday.

Boston College High School, Arlington Catholic High School, The Saint Agnes School, The Abigail Adams and Maria Weston Chapman middle schools, Bourne High School, Quabbin Regional High School, Falmouth High School and Mashpee Middle-High School each received phoned-in threats on Friday. Authorities found no explosive devices at any of the schools, The Boston Globe reported.

The calls on Friday were automated phone messages warning of a bomb detonation “in the very near future,” according to The Globe. Similar calls had been received in Maryland, authorities said.

“[Investigators] don’t take these threats lightly,” Massachusetts State Police spokesman David Procopio told The Globe in an email. “Per state law, bomb threats to schools are not merely charged as a general threat to commit a crime or as annoying and harassing phone calls. Rather, the relevant statue has very severe potential penalties if an individual is found guilty of such a crime.”