An Air National Guard base in Tennessee was placed on lockdown Wednesday over reports of gunfire and a suspicious person armed with a rifle, according to officials.

“Tennessee National Guard security personnel are currently working with state and federal law enforcement at McGhee Tyson Air Base on reports of suspicious activity,” the unit wrote in a Facebook post around 12:50 p.m.

Lt. Col. Travers Hurst told local CBS affiliate WVLT that the base — about 15 miles southwest of Knoxville — was on lockdown after a student reported seeing the possible gunman.

Officials had also received reports of shots being fired, Tennessee National Guard Sgt. First Class William Jones told The Associated Press.

The group said in its Facebook post that no injuries had been reported.

“The situation is developing and more information will be released as it becomes available,” the statement concluded.