US Air Force base locked down after 'gunshot sounds' heard

A U.S. Air Force base near Tucson, Arizona was on Monday locked down over unconfirmed reports of "gunshot sounds" heard there, a base spokeswoman said.

No further details

of the incident at Davis-Monthan Air Force Base were immediately available, according to a spokeswoman for the base.

The base announced the lockdown on social media shortly before 10 a.m. (1700 GMT), saying that there were "unconfirmed reports of gunshot sounds."

An all clear was declared about an hour later and the base said personnel there were "free to resume all normal operations."