HONOLULU (AP) -- All six Marines killed in the crash of a U.S. helicopter in Afghanistan were based in Hawaii, a Hawaii congresswoman said Friday.
The CH-53D helicopter crashed Thursday in Afghanistan's southern province of Helmand.
U.S. Rep. Colleen Hanabusa, a member of the House Armed Services Committee, said Friday she's saddened to hear of the deaths. Her spokeswoman, Ashley Nagaoka Boylan, said the congresswoman was notified Thursday evening that all six Marines were Hawaii-based.
"All who have called Hawaii home are part of our island ohana, and every loss like this touches us deeply," Hanabusa said in a statement, using the Hawaiian word for family.
The military hasn't identified those killed. But John Riddick, of Mount Pleasant, Iowa, said his son was among them.
Master Sgt. Travis Riddick, 40, grew up in Iowa and joined the Marines after graduating from Centerville High School in 1990. John Riddick said his son served three tours in Iraq and two in Afghanistan. This was to be his last tour.
The Vietnam War-era CH-53D is the same model as a helicopter that crashed and killed a Marine in a bay off Hawaii on March 29. An investigation later revealed mechanical failure caused that accident.
Thursday's crash was the deadliest in Afghanistan since August, when 30 American troops died after a Chinook helicopter was apparently shot down in Wardak province in the center of the country.
The cause of the latest crash is still being investigated, but a statement issued by the NATO international military coalition said there was no enemy activity in the area when it happened.
German Brig. Gen. Carsten Jacobson, a spokesman for the NATO coalition in Kabul, said officials were looking at a "technical fault" as the possible culprit.
"The helicopter is one of the safest forms of transport," Jacobson said. He said not only does it protect troops the danger of roadside bombs on the ground, but it is well-tested, well-proven way to travel.
"The loss of the six U.S. Marines in yesterday's helicopter crash in Afghanistan comes as tragic news for our island community and our nation," U.S. Rep. Mazie K. Hirono, of Hawaii, said in a statement. "We owe them and all of our brave servicemen and women a debt of gratitude for their dedication to our country."
In 2005, the same base lost 27 Marines when a CH-53E Super Stallion deployed to Iraq crashed during a desert sandstorm. Altogether, 30 Marines and a Navy medic were killed in that crash.
CH-53D Sea Stallion helicopters were first used in the 1960s, and the Marine Corps flew them in the Vietnam War.
All Sea Stallions still used operationally are stationed at Marine Corps Base Hawaii in Kaneohe Bay. The military plans to replace them with the MV-22 Osprey.
AP National Security Writer Robert Burns in Washington contributed to this report.