An air base in the US state of Arizona has been placed under partial lockdown, amid an unspecified security situation.
Davis-Monthan Air Force Base officials said the measure was taken due to "suspicious activity". Traffic has been limited around the facility.
They denied a local media report that shots had been fired or that someone had been injured.
A fire spokeswoman told AP news agency two ambulances had been sent to the base, which is near Tuscon.
There are two elementary schools on the base, but there were no reports of harm to any students.
Local television station KVOA reported via its Twitter account that the Tucson Fire Department was responding to the base "for possible patient with multiple gun-shot-wounds".
But a short time later an unnamed base spokesman said: "No shots have been fired and no-one has been hurt.
"Reports of suspicious activity have caused DM [Davis-Monthan] officials to declare a higher state of security. We are conducting investigations." Source