BAGRAM, Afghanistan -- The twisted wreckage of a U.S. helicopter lay on an Afghan plain Friday as troops searched for clues to a crash that killed four members of an elite unit that slips special forces commandos behind enemy lines.
The hulk of helicopter lay near Bagram Air Base, with snow-covered mountains far in the distance. The military said it was unsure what caused Thursday's crash. There was no indication of enemy fire.
The victims were identified as Chief Warrant Officer Mark S. O'Steen, 43, of Alabama; Chief Warrant Officer Thomas J. Gibbons, 31, of Maryland; Sgt. Gregory M. Frampton, 37, of California; and Staff Sgt. Daniel L. Kisling Jr., 31, of Neosho, Mo.
Hometowns for the other soldiers were not immediately available.
O'Steen and Gibbons were pilots. Kisling and Frampton were maintenance crewmen.
"These men gave their lives in the defense of freedom, doing what they loved most, flying with the 160th," Lt. Col. Emmett Shaffer, the regiment's deputy commander, said Friday. "I ask for your prayers, both for those we have lost, and those who continue our mission."
Kisling leaves behind a pregnant wife, Georgie, and three children between the ages of 3 and 13. His brother-in-law, Jon McNeill, said Kisling was an excellent husband and father and dedicated serviceman.
"He loved his job," McNeill said. "He was 200 percent Army."
The special operations helicopter went down Thursday night seven miles east of the air base while on a training mission.
It was the deadliest day for the American military in Afghanistan since March 4, 2002, when seven soldiers were killed and 11 wounded at the outset of Operation Anaconda against remnant Taliban and al-Qaida forces.
"It always hurts when you hear" that an army helicopter has gone down, said Chief Warrant Officer Stan Kosiatek, a Black Hawk pilot. "We don't know why it went down, we just know it was one of our fellow aviators."
The helicopter that crashed is known as the MH-60, an adapted version of the Black Hawk which Army special operations forces use for long-range, low-level penetration of hostile territory at night.
Col. Roger King, spokesman for the U.S. military at the Bagram base, said the crash was not connected to continuing U.S. military operations in southeast Afghanistan, where troops backed by helicopters were scouring caves in the Adi Ghar mountain for rebel fighters.
The U.S. military relies on helicopters in Afghanistan because there are few good roads or airfields, the terrain is steep and rugged, and many routes remain littered with mines.
But Afghanistan's roiling dust often clogs engines, and the high altitude of Bagram strains rotors. Bagram lies nearly 1 mile above sea level and the thinner air reduces the lifting capacity of helicopters.
"Afghanistan is a tough place to fly," King said.
Any changes in the U.S. military's aerial operations would depend on conclusions of the investigation into the crash, King said.
Since U.S. military action in Afghanistan began in October 2001, at least six U.S. helicopters have crashed or had hard landings that have injured or killed troops. Two Army Rangers and two Marines have been killed, and at least 11 other troops have been injured.
Including the latest casualties, the U.S. military has had 25 soldiers killed in action in Afghanistan since the war on terror began. Twenty-two deaths were due to non-battlefield incidents.
Nine other Night Stalkers have died in America's war on terrorism since Sept. 11, 2001.
King said the 8,000 U.S. soldiers based in Afghanistan would rebound from the latest loss.
"They recognize that this is part of what they do, they still have a job to do and they'll get on with it," he said.