There was no enemy involvement in the air crash that killed an airman from Upper Marlboro in Africa over the weekend, the Pentagon said Tuesday.

Senior Airman Julian S. Scholten, 26, was one of four special operations airmen killed Saturday when their single-engine U-28 turboprop crashed six miles from Djibouti-Ambouli International Airport, according to the U.S. Africa Command.

"This is obviously a tragic incident," Pentagon Press Secretary George Little said Tuesday, according to the American Forces Press Service. "There is absolutely no indication of any kind of enemy involvement in the downing of the plane."

Little said the airmen had been conducting a surveillance and reconnaissance mission in support of the global war on terror. The airport in Djibouti City is near Camp Lemonnier, the main U.S. base for antiterror operations in the Horn of Africa.

Scholten was assigned to the 25th Intelligence Squadron at Hurlburt Field, Fla., according to the Pentagon.

Also killed were Capt. Ryan P. Hall, 30, of Colorado Springs, assigned to the 319th Special Operations Squadron at Hurlburt Field; and Capt. Nicholas S. Whitlick, 29, of Newnan, Ga., and 1st Lt. Justin J. Wilkens, 26, of Bend, Ore., both assigned to the 34th Special Operations Squadron at Hurlburt Field.

Officials held a transfer ceremony for their remains early Tuesday at the Dover Air Force Base military mortuary in Delaware.

A safety board investigation has been launched to determine the cause of the incident, according to Africa Command.

"We need to understand precisely what happened," Little said.