A Tennessean was among the three U.S. Special Forces soldiers killed in Afghanistan Wednesday when a U.S. bomb missed its Taliban target.

The Pentagon identified those killed as Master Sgt. Jefferson Donald Davis, 39, of Watauga, Tenn.; Sgt. 1st Class Daniel Petithory, 32, of Cheshire, Mass.; and Staff Sgt. Brian Cody Prosser, 28, of California.

All were members of the Army's 3rd Battalion, 5th Special Forces Group, stationed at Fort Campbell, Ky.

The bomb, carrying 2,000 pounds of explosives, landed about 100 yards from the soldiers' position north of Kandahar, where the Taliban is making its last stand against Afghan opposition forces. Nineteen other American soldiers were injured and five Afghan fighters were killed.

Pentagon officials said they could not immediately explain what went wrong in the deadliest "friendly fire" accident of the war.

Davis, a Green Beret sergeant, lived with his wife and three children in Clarksville. His parents, William Lon and Linda Davis, traveled Wednesday from Watauga to Clarksville to be with their daughter-in-law and grandchildren.

Cousin Penny McCracken told the Johnson City Press that Davis was career military and his family was proud of his service.

"He was always a good guy," she said.

The newspaper reported that Davis was a 1981 graduate of Elizabethton High School, where he played football and basketball. He also played football while attending Lees-McRae College in Banner Elk, N.C. He later studied nursing at East Tennessee State University.

Sen. Bill Frist, R-Tenn., said Davis died serving his country and as a hero.

"My thoughts and prayers go out to the Davis family and friends during this difficult time," Frist said in a statement. "I hope his family will find comfort in knowing that Donny died a hero and that his death is grieved by all Americans. He gave the ultimate sacrifice for the freedoms we enjoy and that is something that wont be forgotten by our nation."

The 22 American soldiers were described as special operations forces, but officials would not say whether they were Green Berets, Rangers, or other kinds of special operations troops. It appeared likely most were Green Berets.

The deaths bring to four the number of Americans killed inside Afghanistan in the two-month war. CIA officer Johnny "Mike" Spann was killed Nov. 25 in a prison uprising while questioning forces captured in the fighting.