The tight-knit Kaneohe Bay military community paid tribute this morning to the 12 Marines who were killed last week during a routine training mission when two cargo helicopters collided and crashed off Oahu’s North Shore.

At a memorial service near helicopter Hangar 102 where the night mission began a little more than a week ago, the roll call for the air crew was called for the last time.

President Obama issued a statement expressing condolences to the families of the fallen Marines.

“Communities from coast-to-coast are mourning these Marines, and our nation is forever grateful for their patriotism, service, and sacrifice,” he said. “Our thoughts and prayers are with their families and loved ones at this difficult hour.”

Lt. Col. Eric Purcell, squadron commander of the fallen aviators, recounted although the Marines were in the prime of their life, but their deaths not “useless” because they were working to create a detriment to the nation’s foes.

The fallen were members of Marine Heavy Helicopter Squadron 463, Marine Aircraft Group 24, 1st Marine Aircraft Wing.

Two of the 12 CH-53E Super Stallion helicopters belonging to Squadron 463 flanked 12 crosses representing the fallen Marines. The flags of 50 states fluttered in the morning tradewinds behind the white crosses with Kaneohe Bay and the Koolau Mountain Range providing a dramatic backdrop.

In front of the two helicopters were larger-than-life color portraits of the crew of Pegasus 31 and Pegasus 32:

» Maj. Shawn M. Campbell, 41, pilot, from College Station, Texas, who joined in 1999.

» Sgt. William J. Turner, 25, crew chief, from Florala, Ala., who joined in 2008.

» Capt. Kevin T. Roche, 30, pilot, from St. Louis, who joined in 2005.

» Capt. Brian T. Kennedy, 31, pilot, from Philadelphia, who joined 2003.

» Sgt. Jeffrey A. Sempler, 22, crew chief, from Woodruff, S.C. , who joined in 2010.

» Sgt. Adam C. Schoeller, 25, crew chief, from Gardners, Pa., who joined in 2008.

» Sgt. Dillon J. Semolina, 24, crew chief, from Chaska, Minn. , who joined in 2011.

» Cpl. Thomas J. Jardas, 22, crew chief, from Fort Myers, Fla. , who joined in 2011.

» Cpl. Christopher J. Orlando, 23, crew chief, from Hingham, Mass., who joined in 2012.

» Capt. Steven R. Torbert, 29, pilot, from Florence, Ala. , who joined in 2004.

» Cpl. Matthew R. Drown, 23, crew chief, from Spring, Texas, who joined in 2011.

» Lance Cpl. Ty L. Hart, 21, crew chief, from Aumsville, Ore. who joined 2012.

Besides family members, the memorial service was attended by the leaders of Hawaii’s military and civilian communities.

Fellow Marines provided personal reflections during the ceremony.

The service was not open to the public but was live-streamed on the Pacific Marines YouTube channel and several commercial television stations.

In a tribute to the Marines, Gov. David Ige has ordered the flags of the United States and Hawaii to be flown at half-staff at all state buildings and agencies from today through Tuesday.

In issuing the proclamation, Ige said: “These 12 brave U.S. Marines paid the ultimate price in protecting our freedom of democracy. We mourn their loss and honor their sacrifice and commitment to serving our great state and nation, as our national and state symbols fly at half-staff in their memory. — Never forgotten.”

As the Marines honored the fallen aviators, the search to recover the downed aircraft on the other side of the island continued today.

The recovery effort is being conducted from a command post at Haleiwa Alii Beach Park, which remains closed.

All vessels are prohibited within a mile of the crash site located 2.5 miles northwest of Haleiwa Small Boat Harbor while the Marines conduct salvage operations to recover the wreckage and debris of two large CH-53E Super Stallion cargo helicopters.

The safety zone went into effect Wednesday and will remain in effect until Feb. 10 or until salvage operations are completed, the Coast Guard said.

Kaneohe Marines aided by the USNS Salvor, a Navy salvage vessel, and divers from Mobile Salvage and Diving Unit 1 are conducting the salvage operation.

The dive unit played a key role in the recovery of the bodies of eight of the nine missing crewmembers and personal effects following the collision of the nuclear submarine USS Greeneville and the Japanese training fishing vessel Ehime Maru off Diamond Head in 2001, the salvage of the cruiser Port Royal off Waikiki in 2009 and recovery of the older CH-53D Sea Stallion from Marine Heavy Helicopter Squadron 363 that crashed on a Kaneohe sandbar in 2011 killing one Marine.

Besides the Ehime Maru recovery mission, the Salvor participated in seven sea-recoveries of submerged military aircraft, including an A-6E Intruder (VA-145) in Puget Sound, Washington, a UH-46D Sea Knight from a world-record depth 17,251 feet near Wake Island, a SH-60 Seahawk, an F/A-18C Hornet (VFA-22) near San Diego, and two F-16 Falcons in Korean waters and the Sea of Japan.

A massive combined sea and shoreline search effort, which covered more than 53,600 square miles of ocean and shoreline between Haleiwa and Kahuku, was coordinated from the Haleiwa command post for five days following the crash just before midnight Jan. 14.

It was suspended Tuesday at sunset when no survivors were located.

A debris field was found on the seafloor in 325 feet of water two miles off Haleiwa.

All the wreckage and debris recovered will be moved to the Marine Corps Base Hawaii for analysis as part of the military accident investigation. Because the crash involved two military helicopters, the National Transportation Safety Board is not conducting its own investigation.

Besides crash debris, searchers recovered four life rafts carried by the two CH-53E Super Stallion helicopters, which each had a crew of six.

Last week’s crash is the worst non-combat training exercise in Hawaii for the military.

On Feb. 12, 2001, six Schofield Barracks soldiers were killed and 11 were injured when two Army Black Hawk helicopters crashed during a routine training exercise at the Kahuku Military Training Reservation on Oahu’s North Shore.

On the night of the collision, helicopters were carrying soldiers from the 25th Division’s 2nd and 3rd Brigade, and equipment in three groups of four as part of a large North Shore exercise. All six casualties came from a helicopter carrying an Army Humvee in a sling beneath it.