Polish local media said military prosecutor Mikolaj Przybyl was taken to a hospital after reporters found him lying on the floor of his office in a pool of blood only seconds after the departing journalists heard a gunshot coming from his office.
Przybyl had asked the reporters to leave his office after he criticised media leaks from the continuing probe into the plane crash in Russia on 10 April, 2010 that killed then-president Lech Kaczynski and 95 others, mostly senior Polish officials.
During his brief news conference, Przybyl said the military prosecutor's office in the western city of Poznan had the right to seek phone records of journalists covering the investigation of the 2010 air crash.
Several news outlets showed footage of Przybyl's body behind his desk before an ambulance took him to a hospital.
Broadcaster TVN quoted a military spokesperson as saying that Przybyl's life was not in danger.
Polish President Bronislaw Komorowski said in a statement he was "concerned" about the suicide attempt and asked the head of the national security bureau to monitor the situation.