A lockdown of the Ault Field base at Naval Air Station Whidbey Island was lifted just before 10 a.m., but access is still limited, according to the base public affairs officer.

Navy security did not locate any evidence there there was gunfire and there’s no reports of casualties, a press release states.

A sailor on base reported hearing what sounded like gunfire at about 5 a.m.

“Out of abundance of caution base officials secured access to and from Ault Field and took all necessary steps to ensure the safety of our personnel,” the Navy press release says.

All personnel on base were ordered to shelter in place; the order has been lifted.

Areas of the base were cordoned off as base security officials continue the investigation. All personnel should stay clear of the cordoned off areas, the Navy reported.