On Aviation and Air Force Day, President Rumen Radev pointed out that the day was darkened by the death of the two pilots, whom we continue to mourn for. "I cannot comment on hypotheses before all the facts about this accident are available," the president said after the solemn ritual of laying wreaths and flowers.

On September 13 at the "Graf Ignatievo" base, two pilots on board an L-39ZA trainer aircraft died in crash during a display training session.

• Two pilots killed as military plane crashes while training for air show

"The Ministry of Defense has made it clear that the immediate and accompanying cause are known, but finding guilt and the imputation of responsibility is not the subject of this investigation," the head of state said, adding that the work of the prosecutor's office and the commission appointed for the purpose continues. He also expects a thorough analysis from the Ministry of Defense and an explanation from the Defense Committee in parliament.

• Crashed L-39 military trainer aircraft was technically sound

Imputation of responsibility, political interference and attempts to demand resignations while the authorities are working on the case are unethical and immoral, Rumen Radev says.