At least two central Maine high schools were evacuated Tuesday morning after authorities received threats of bombs on the campuses.

Students and staff at Cony Middle and High School and Madison Area Memorial High School returned inside the buildings after law enforcement investigated the threats, according to school officials.

The Augusta Communications Center, which answers 911 calls, received the bomb threat over the phone, Augusta Deputy Police Chief Kevin Lully said in a news release. An automated call containing similar information was received by several other schools and local law enforcement agencies across the state Tuesday.

Cony Middle and High School was evacuated at 10 a.m., while the resource officer, patrol officers, detectives and a state police K-9 team responded to “secure the school.”

Students returned back to their classes around 10:40 a.m.

Kim Silsby, principal of Cony Middle and High School, wrote a Facebook post to share the news with parents and said the students were ushered outside due to “an abundance of caution.” She has not said anything to the public since classes resumed.

Who made the threat, or what exactly the threat said, is still unknown.

“It was not a message, rather the dispatcher was asking questions of the caller, which were being answered,” said Lully. “That doesn’t mean a voice automation software wasn’t being used, but it was not simply a message left on a voicemail box.”

Around the same time, Madison Area Memorial High School was also evacuated because of a threat.

Authorities were contacted shortly after 9:30 a.m. Tuesday after Madison Area Memorial High School received an automated message claiming a bomb was on campus, according to Chief Deputy Michael Mitchell of the Somerset County Sheriff’s Office. Students were bused down the street to Madison Junior High School as law enforcement personnel with K-9s searched the high school. Nothing suspicious was found and students were returned to the high school to resume classes.

Mitchell said the call was automated and similar to one received by the 911 dispatch center in Augusta about Cony High School.

Several other schools across the state reported receiving automated messages about bombs, including in the Aroostook County towns of Fort Fairfield, Limestone, Madawaska and Van Buren.

Madawaska police said on the department Facebook page that they plan to have a heightened presence at the middle and high school for the remainder of the week. Fort Fairfield police Chief Matthew Cummings said on Facebook that the middle and high school was evacuated before his officers were joined by U.S. Border Patrol agents in searching for suspicious devices.

A spokesman for the Maine Department of Education, Marcus Mrowka, said the department did not know the number of Maine schools that received threats but said there were several and that schools in other states also received them. None of the threats called in to Maine schools were credible, he said.

Morning Sentinel staff writers Taylor Abbott and Haley Hersey contributed to this report.