A sailor killed two people Wednesday afternoon at the iconic Pearl Harbor base before fatally turning his gun upon himself.

Rear Adm. Robert Chadwick told reporters at an early evening news conference that three civilian Defense Department workers had been shot, two fatally, and the third victim was in stable condition.

The gunman, identified as a Navy sailor, died “of a self-inflicted gunshot wound,” he said at Joint Base Pearl Harbor-Hickam.

A witness told Hawaii News Now that while sitting at his desk near Drydock 2 around 2:30 p.m., he heard loud pops.

“I kind of recognize that as gunshots,” the witness told the site. “And I looked out the window and saw three people on the ground.”

Base officials said on Twitter that the names of the victims and the gunman will not be released until the next of kin have been notified. There also was no immediate indication of a motive.

Gov. David Ige said the White House has offered assistance.

“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,” Mr. Ige said.

The attack occurred just three days before the anniversary of Japan’s sneak attack on the U.S. fleet there on Dec. 7, 1941.