The commander of an Air Force base in southern Arizona has said no gunman or weapons were found in response to unconfirmed reports of a gunman.
Colonel John Cherrie, commander of Davis-Monthan Air Force Base on the outskirts of Tucson, said officials were satisfied that the base was safe again after an extensive search at the base.
Col Cherrie held a two-minute news conference to discuss the five-hour lockdown of the base on Friday.
A military official had earlier said that a man with a gun was hiding in a building at the base.
The lockdown at the sprawling facility was prompted by reports of someone with something that looked like a weapon.
The reports prompted a frenzy of activity at the base and in the news media amid unsubstantiated reports that someone had been shot.