HONOLULU - Officials will beef up security as usual for the ceremony to remember those lost in the attack on Pearl Harbor 78 years ago, with service members and dignitaries confronting a fresh tragedy after a U.S. sailor killed two civilians, wounded another and then turned the gun on himself at the storied military base.

The National Park Service, which is hosting the event with the Navy, would not give specifics on the heightened security measures, many of which aren't readily apparent, Pearl Harbor National Memorial spokesman Jay Blount said.

The commemoration of the anniversary of the Japanese bombing that propelled the United States into World War II will go on as planned Saturday, he said. It's expected to draw survivors, veterans, dignitaries and the public to honour more than 2,300 Americans who perished on Dec. 7, 1941.

“We have not heard of anyone cancelling plans to attend the event due to security concerns and want the public to know that it will be a safe, fun and enjoyable day for everyone,” Blount said.

Across the harbour at the naval shipyard, a sailor shot three men working for the U.S. Department on Defence on Wednesday, killing two, before taking his own life. The wounded victim was hospitalized in stable condition.

The gunman was 22-year-old G. Romero, according to a military official who spoke on condition of anonymity to provide details that had not been made public.

Romero's job was to stand watch on the fast attack submarine USS Columbia, which is at Joint Base Pearl Harbor-Hickam for maintenance. He used his service rifle to shoot the victims, then killed himself with his service pistol, the official said.

Rear Adm. Robert Chadwick, commander of Navy Region Hawaii, said he didn't know the motive for the shooting. It wasn't known if the sailor and victims knew each other, he said.

“We have no indication yet whether they were targeted or if it was a random shooting,” Chadwick said.

Tara Kapoi told The Associated Press that her 30-year-old husband, Vincent Kapoi Jr., was one of those killed. She said he worked at the shipyard and grew up in Waianae, a town on the west side of Oahu.

“We don't know what happened,” she said Thursday, asking for privacy.

William and Sista Kahiamoe have lived next door to the Kapoi family for about 21 years. They say Vincent's brother now lives in the home.

William Kahiamoe said Vincent Kapoi followed his father into civilian work at Pearl Harbor Naval Shipyard.

“He was a good boy, I know that. Took care of his mom when she was sick,” Sista Kahiamoe said. “He was really good, and he was the oldest child.”

College roommate Daniel Vu described Kapoi as a “family guy” who was soft-spoken and extremely hardworking, known for waking up at 3 a.m. to work at the fishing docks to pay for tuition. He told news website Honolulu Civil Beat that Kapoi graduated from the University of San Francisco in 2011 and was proud of his Native Hawaiian and Filipino heritage.

“He was very giving, very generous and willing to sacrifice a lot,” Vu said. “He was one of the good guys out there.”

Names of the other victims have not been released.

Mass shootings and gun violence are rare in Hawaii. It had the lowest gun death rate among the states in 2017, according to the Giffords Law Center to Prevent Gun Violence. State law prohibits fully automatic weapons but allows some semi-automatic weapons like AR-15 rifles.

In 1999, a Xerox service technician shot and killed seven coworkers in Hawaii. In 2006, a man fatally shot his taxi driver and a couple taking photos of the city lights from a lookout point in the hills above Honolulu.

The shipyard repairs, maintains and modernizes the ships and submarines of the U.S. Pacific Fleet, which is headquartered at Pearl Harbor. The base is the home port for 10 destroyers and 15 submarines. It also hosts Air Force units.

Associated Press writers Lolita C. Baldor in Washington, Mark Thiessen and Rachel D'Oro in Anchorage, Alaska, Becky Bohrer in Juneau, Alaska, and researcher Rhonda Shafner in New York contributed to this report.

Correction - Dec. 11, 2019 -- In a Dec. 5 story about a shooting at the Pearl Harbor military base, The Associated Press erroneously reported that all assault weapons and high-capacity ammunition magazines are banned in Hawaii. State law prohibits fully automatic weapons but allows some semi-automatic weapons like AR-15 rifles. Hawaii prohibits magazines from having more than 10 rounds for handguns but allows large-capacity magazines for rifles.