UPDATE 4:30 p.m:

Two phoned-in bomb threats claiming an explosive device was on the destroyer USS William P. Lawrence in the shipyard’s Dry Dock 4 led to a lengthy Joint Base Pearl Harbor-Hickam lockdown today, bottling up thousands who were told to shelter in place and avoid windows in the event of flying glass, officials said.

Personnel working in Dry Dock 4, where work on surface ships is conducted mainly by contractors, were evacuated to Dry Dock 1 during the lockdown, officials said.

Bomb-sniffing dogs could be seen working along the waterfront. No bomb was found, the joint base said. Motorists who were not able to leave the joint base due to the lockdown vented their frustration on social media.

At 9:39 a.m., entrances to the joint base were secured and the shelter-in-place order was given for what the base referred to as a “security incident.”

The Hickam side of the base ended its shelter order first, followed by an “all clear” that cancelled the security watch at about 1:30 p.m.

A “person of interest” was sought out, questioned, and found to have no involvement, an official said.

Units from the Honolulu Police Department and Federal Fire Department responded to assist in the investigation with joint base security and other emergency personnel.

Tours to the USS Arizona Memorial and other museums in Pearl Harbor have resumed, the joint base said in a release.

“During the investigation, those tours were suspended, and guests at both the USS Missouri Memorial and the Pearl Harbor Aviation Museum on Ford Island sheltered in place as well,” the base said.

“We are grateful to the first responders who helped us investigate and secure the potential incident,” Col. Tammie Harris, the deputy joint base commander, said in a release. “I want to assure everyone that we will do everything possible to maintain the operational readiness of JBPHH while protecting the safety of our base employees, our service members and their families.”

The Hawaii Regional Maintenance Center docked the Pearl Harbor-based William P. Lawrence on March 9 in Dry Dock 4 in the shipyard for maintenance.

The approximately $90 million in repairs and upgrades is expected to include a major combat systems installation. The regional maintenance center is partnering with Vigor Marine on the project.

“The HRMC and Vigor team is laser-focused on executing first-time quality work that will return the ship back to sea on time for her crew,” J.C. “Harry” Herrera, the maintenance center project manager for the job, said in a March 11 Navy release.

The job marks the first time Pearl Harbor shipyard has docked a berthing and messing barge alongside a ship in Dry Dock 4 providing working and living space for the ship’s crew when work prevents them from living aboard the ship.

The shipyard, which is the state’s largest industrial employer, said it has a combined civilian and workforce of about 6,500 along with 700 contractors and an annual economic impact of $1 billion.

2:20 p.m.

At about 1:45 p.m., Joint Base Pearl Harbor-Hickam posted to Facebook: “All clear. No hazardous conditions exist. Resume normal operations.”

Dry Dock 4 personnel in the Pearl Harbor Naval Shipyard, where work on surface ships is conducted mainly by contractors, were evacuated to Dry Dock 1 during the lockdown, officials said.

Bomb-sniffing dogs could be seen working along the waterfront.

The joint base earlier said, “Personnel should stand clear of cordoned areas North of South Avenue and West of North Road.”

1:35 p.m.

All gates are open at Joint Base Pearl Harbor-Hickam, and a shelter-in-place order “has been lifted for most areas,” the base said.

The base could not specify if the all-clear was given for the Dry Dock 4 area, or the exact nature of the threat that led to the lengthy lockdown.

1:20 p.m.

Joint Base Pearl Harbor-Hickam is no longer on lockdown, authorities say.

This breaking news story will be updated as more details become available.

PREVIOUS COVERAGE

Joint Base Pearl Harbor-Hickam was on lockdown as of 10:30 a.m. today due to the possibility of a bomb threat on a ship. No details of the threat were immediately available from the joint base.

Just after 11 a.m. the base sent a release saying, “There has been a potential security incident aboard Joint Base Pearl Harbor. All hands are directed to shelter in place north of South Avenue and west of North Avenue.

“At this time all gates to the installation have been secured. All vehicles should limit their travel on the roadways, and yield to responding emergency vehicles. All tour operations to the USS Arizona Memorial have been suspended for now.

“The investigation is ongoing, and additional information will be passed as it is made available.”

Ironically, the joint base warned of the sound of gunfire due to training on an annual exercise called “Citadel Protect” that started Monday and provides anti-terrorism and “force protection” training for Pearl Harbor-based sailors.

The current lockdown is due to an actual threat and is not related to the training.

“Beginning TODAY, Tuesday, June 8, the training will involve the use of blank rounds fired from Crew Served Weapons such as M240s (belt-fed machine guns) in the vicinity of the harbor. Base personnel, residents and those who live near the installation should not be alarmed by the sounds of gunfire, other popping noises and activations of the base-wide Giant Voice System,” the joint base said on Facebook.

In a news release about Citadel Protect, the joint base said: “Residents and personnel who live and work on (the joint base) may see increased traffic and delays in base access. The exercise involves various training scenarios that replicate real-world events, and is designed to enhance the readiness of Navy security forces to respond to threats to installations and units. Citadel Protect is a regularly scheduled exercise and is not in response to any specific threat.”

Because of the planned exercise, confusion resulted as to the source of the lockdown, with some saying the very real security measures are due to a bomb threat. The base did not confirm the information.