SOFIA (Reuters) - A Bulgarian military helicopter crashed into the Black Sea off the Bulgarian coast during tactical drills on Friday, killing one officer and injuring two others, the defense ministry said.

The helicopter, an AS 565MB Panther, crashed after carrying out a maneuver following artillery shooting drills, the ministry said in a statement, adding that the reasons for the crash are being investigated.

The helicopter’s commander died later in hospital, while the other two officers on board were in a stable condition, the ministry said.

NATO member Bulgaria has stepped up military drills over the past two years as part of the alliance’s efforts to better protect the region from any potential threat from Russia.