Sailor shoots civilians at Pearl Harbor
A US Navy sailor has shot three civilians at the Pearl Harbor base in Hawaii before turning the gun on himself.
Joint Base Pearl Harbor-Hickham sent out a tweet confirming the sailor opened fire on three Department of Defence contractors.
The shooter is confirmed dead, and two of the victims are in a critical condition. The third's condition is unknown.
Staff at the base were sent a message warning of an active shooter at about 2.30pm local time (11.30am AEDT).
"All personnel are advised to lockdown at their location," the message read.
"If inside, stay inside, if outside find a secure location.
"Be vigilant, report emergencies and suspicious information to the authorities and follow the instructions of local responders."
Three schools, including two on the base itself, went into lockdown, though most students had already left for the day.
The base is no longer in lockdown.
Hawaii's governor David Ige has expressed his grief and resolve.
"I join in solidarity with the people of Hawaii as we express our heartbreak over this tragedy and concern for those affected by the shooting," he said.
Pearl Harbor is one of the US Navy's major installations.
The shipyard is across the harbour from the Pearl Harbor National Memorial, which on Saturday will mark the 78th anniversary of the attack by Japan that propelled the US into World War II.
The unexpected attack on December 7, 1941, resulted in the sinking of four battleships and the deaths of 2335 people.
Nearly 200 aircraft were destroyed and more than a dozen other warships were damaged.
Pearl Harbor houses the headquarters for the US Pacific Fleet and is the home port for 10 destroyers and 15 submarines.
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-With Associated Press