Davis-Monthan Air Force Base in Arizona was placed on lockdown Friday after authorities received unconfirmed reports of gunman being sighted on the premises.
Officials at the facility reported there that there was a "potential security situation" after someone reportedly saw a man with a weapon at an old dormitory building on the base.
Local television station KVOA reported on its Twitter account that the Tucson Fire Department was responding to the base for a "possible patient with multiple gun-shot-wounds."
However, an investigation revealed that no shots had been fired and that no one had been injured.
"No shots have been fired, no one is hurt," said base spokesman Tech Sgt. Russell Martin, according to MSNBC.
"So the base is going into crisis action mode. We're just locking down the base for the safety and security of the people on Davis-Monthan," Martin said, according to the Associated Press (AP).
Emergency services personnel reported to the base, but later reports indicated that they were responding to a woman on base who was in labor.
KVOA also reported around 5:00 p.m. that a SWAT team and bomb quad had arrived on base.
Two schools on the base were locked down, according to CNN. The perimeter and classroom doors were locked and students were told to remain where they were, said Karen Bynum, executive assistant to Superintendent John Pedicone.
Senior Airman Timothy Dunaway told the AP that traffic had been reduced to a single point of entry as an investigation into the sighting of an armed individual was being pursued.
Davis-Monthan AFB is five miles southeast of downtown Tucson.
Security at military bases has increased in the last two years since an Army Maj. Nidal Hasan allegedly killed 13 people in a shooting rampage at Fort Hood in Texas in November 2009.
Hasan faces 13 counts of premeditated murder and 32 counts of attempted premeditated murder. His trial is set for March 2012.