The name of the American pilot is being withheld pending next of kin notification, Bowyer-Meeder said.
The General Staff of Ukraine's armed forces said the two-seat Su-27UB went down in the Kmelnitskyi region.
The joint military training was billed as the "first-ever Clear Sky exercise", to be held primarily at Starokostiantyniv Air Base in Ukraine as well as other training areas and ranges in the region.
Petrenko was the experienced Air Force officer, fully trained to act as an instructor during combat missions in both day- and nighttime, in complicated weather conditions. Gen. Clay Garrison, California ANG commander and Clear Sky exercise director.
"We regret to inform that according to the rescue team, the bodies of two pilots have been discovered: one is a serviceman of the Ukrainian Air Force, the other is a member of the US National Guard", it said. The Ukranian air force said that training flights of all types of aircraft would continue, according to UNIAN.
Military prosecutors in Ukraine's Central region have launched an inquiry.
Though we don't yet know the exact reason why the USA pilot was flying in the Flanker, Approximately 950 personnel from Belgium, Denmark, Estonia, The Netherlands, Poland, Romania, Ukraine, the United Kingdom, and the United States are taking part in the drills.
Ukraine is not a North Atlantic Treaty Organisation member but has declared interest in joining the alliance.