veteran smokejumper for the U.S. Bureau of Land Management has died after parachuting from a plane during a training exercise in Idaho, the first such accident in 13 years, an agency spokesman said on Saturday.

It was unclear if an equipment flaw, medical emergency or weather conditions caused the death on Friday of Mark Urban, 40, of Boise, said Bureau of Land Management spokesman Ken Frederick.

Urban was one of a team of highly skilled federal firefighters jumping from a plane about 45 miles east of Boise in an exercise designed to maintain their parachuting proficiency, Frederick said.

Urban was the second firefighter to jump out of the aircraft during the practice "when something - we don't know what - went wrong," he said.

An investigation of the incident by U.S. fire managers was under way, he said.

A paramedic pronounced Urban dead near a landing site outside the agricultural community of Prairie, Idaho.

It was the first fatal accident in 13 years involving a Bureau of Land Management smokejumper engaged in a proficiency drill. In 2000, an agency smokejumper leaped from a plane to his death in Alaska after his parachute malfunctioned, Frederick said.

The incident on Friday brings to 33 the number of U.S. wildland firefighters who have died on the job so far this year.

Urban was a 10-year veteran and trainer with a bureau base in Boise with roughly 80 smokejumpers, who parachute into remote and rugged terrain to fight fires. The 450 smokejumpers with the Bureau of Land Management and the U.S. Forest Service are seasonally required to parachute from planes at least once every two weeks to hone their skills.

Urban had tallied 324 jumps, including 102 into fires, since joining the Great Basin Smokejumpers in 2003.

"It's tragic. He was a very popular and well-respected member of the crew and everyone has been hit hard by his death," he said.