The incident occurred during a routine training exercise ahead of a special air show celebrating the 20th anniversary of Bulgaria's accession to NATO.

The pilots, both instructors from the air force school in Dolna Mitropolia, had been scheduled to participate in the air show tomorrow. The flight, which had been planned well in advance, involved the repeated execution of complex maneuvers at a low altitude.

Officials have confirmed that the aircraft involved in the crash had undergone a major overhaul in the Czech Republic earlier this year. Investigations into the cause of the crash are ongoing.

The tragic accident has cast a shadow over the upcoming NATO celebration, with condolences pouring in for the families of the deceased pilots. (ILKHA)