Poland's defense minister says a plane crash that killed the nation's president in 2010 in Russia was preceded by two explosions on board, calling on Russian President Vladimir Putin to "take responsibility for what happened."

Antoni Macierewicz was reacting Thursday to words by Putin, who denied any explosions on board and called on Poland to stop investigating for any potential Russian role in the crash that killed Poland's President Lech Kaczynski and 95 others in western Russia.

Macierewicz heads a commission re-investigating the crash and alleges it was preceded by two explosions, which he says would suggest Russia played a role.

Polish and Russian aviation experts concluded it was an accident.

Macierewicz said in a radio interview that Putin "should have the courage to take responsibility for what has happened."