PEARL HARBOR, Hawaii — A military official says a sailor used his service weapons to kill two civilian workers and then himself at Pearl Harbor. 

The official, who spoke on condition of anonymity to the Associated Press, says 22-year-old G. Romero was assigned to stand watch on the USS Columbia submarine undergoing maintenance at the military base in Hawaii

The shooting that also wounded a third civilian comes just days before thousands descend on the base to mark the 78th anniversary of the Japanese bombing that propelled the United States into World War II.  

The identities of the victims have not yet been released. 

The gunshots were reported Wednesday afternoon at Joint Base Pearl Harbor-Hickam just outside Honolulu. 

Rear Admiral Rob Chadwick, the Navy's commander at Pearl Harbor, said the active shooting response was at a dry dock. He said the three men shot were civilian shipyard workers, and that the shooter was an active duty sailor on the USS Columbia who died from an apparent self-inflicted gunshot. Chadwick said he didn’t know the motive behind the shooting 

The base said in a statement that officials reported the shooting incident has been secured. Security at the base and Navy officials are investigating.

The base had tweeted that security was responding to the gunfire reported around 2:30 p.m. at the Pearl Harbor Naval Shipyard. The base's gates have been opened after they were closed and some parts of Pearl Harbor locked down.

According to The Associated Press, the shipyard repairs, maintains and modernizes the U.S. Pacific Fleet, which is headquartered at Pearl Harbor. It is the home port for 10 destroyers and 15 submarines.

The Associated Press contributed to this report.