CHICAGO (CBS) — Lane Tech High School principal Brian Tennison warned parents Wednesday about an adult who has been inappropriate with students near the school campus.

Two different incidents have been reported in which an adult who is not affiliated with the school has “engaged inappropriately” with students near the Jewel-Osco store at 3400 N. Western Ave., just to the south of the school parking lot.

Tennison’s letter was not more specific about what happened.

The students moved away safely and reported the incidents to school staff, Tennison said.

The school in turn notified both Chicago Police and Chicago Public Schools Safety and Security to protect students and staff, the letter said.

The letter advised that students should travel in pairs whenever possible, and should always go to the nearest business or populated area to call for help if they feel threatened in any way.

The letter also advised that students should use phones with good judgment and awareness of their surroundings, and report any suspicious vehicles, people, or behavior to the school immediately.