Terre Haute South Vigo High School was on a lockout Monday as a precaution after receiving two vague, “unverified phone call” threats, according to the district spokesman.

“We have heightened security on campus and are acting out of an abundance of caution,” said Bill Riley, VCSC director of communications.

The numbers were traced and from out of state, Riley said. “The investigation continues and we are working with several law enforcement agencies,” including Terre Haute police.

“We received [two] very vague, incomplete phone calls” that prompted the lockout, as a precaution, he said. The calls went to the main office.

He could not provide details about the nature of the calls.

The school remained on lockout through the end of the school day. “If you think about what we already do with security, lockout is just a little bit of heightened security ... just a little more than we already do,” Riley said.

Lockout means all students have been brought inside and no visitors are allowed. The school day goes on as normal, and students are allowed to leave campus as long as there’s no “hold in place.”

District officials are taking the calls seriously, but did not believe there was a direct threat to student safety, Riley said.

School went on as normal.

“Everyone went to lunch, everyone went to class,” he said.

There were a few classes students could not attend, such as auto body, because those students would have had to walk across a parking lot.

Sue Loughlin can be reached at 812-231-4235 or at sue.loughlin@tribstar.com Follow Sue on Twitter @TribStarSue.

Sue Loughlin has been a reporter at the Tribune-Star for more than 30 years. She covers general news with a focus on education.