In a separate statement, the U.S. Army Europe said that an airborne jump at the Cheshnegirovo airfield was immediately suspended in order to attend to the paratrooper.
"All casualties were immediately transported to local hospitals where one was pronounced dead, one was admitted for further evaluation, and two were treated and released," the statement said.
A source familiar with the incident said the casualties were paratroopers who were jumping early Tuesday morning, in the dark and from a low height. The source said two Americans and a Canadian solder were injured.
Over 5,600 troops are taking part in the exercise Swift Response 2019, led by the U.S. Global Response Force. It began on June 13 at various locations in Bulgaria, Croatia and Romania.In Bulgaria, some 500 airborne troops from the United States, Canada and Italy took part in the drills at the Cheshnegirovo airfield, about 160 kilometers (100 miles) southeast of Sofia.