Pearl Harbor Naval Shipyard is on lockdown amid reports of a shooting on the base.
At least two people have been critically injured, according to local reports. A third has also been injured.
The incident is said to have taken place at Drydock 2 on Wednesday afternoon, local time.
The shooter is now said to be 'secured' after personnel at the base were told to take cover, Hawaii News Now reports.
Emergency crews raced to the scene at around 2:30pm local time. Text messages are said to have been sent those in the area alerting them of the danger. Footage from the scene show law enforcement and first responders at the scene.
Joint Base Pearl Harbor-Hickam tweeted: 'JBPHH security forces have responded to a reported shooting at the Pearl Harbor Naval Shipyard. 'The incident occurred at approximately 2:30 p.m. Due to the ongoing security incident, access/gates to #JBPHH are closed. We will update when we have further information.'