WARSAW, Poland (AP) — Polish leaders and families of some crash victims attended the premiere Monday of a divisive movie that supports a theory that the 2010 plane crash that killed Polish President Lech Kaczynski and 95 others was an assassination orchestrated by Russia.

The crash in western Russia was among Poland's greatest tragedies since World War II and sparked speculations as to its causes.

Polish and Russian experts blamed bad landing conditions in dense fog at Smolensk airport and pilot errors.

But Kaczynski's party insists that it was an assassination inspired by the Kremlin as punishment for his support for Georgia during its armed conflict with Russia. Moscow vehemently denies the allegations.

Kaczynski's party, the conservative and nationalist Law and Justice, is in power in Poland now..

Kaczynski's twin brother, Jaroslaw Kaczynski, is the ruling party's leader and considered by many to be Poland's most powerful politician. He has blamed his brother's death on Moscow and on Poland's centrist government in 2010.

Russia has refused to return the wreckage, and the identification of some bodies was done incorrectly in Moscow — fueling a theory of foul play among many Poles.

Director Antoni Krauze said the film, called "Smolensk," was a "protest against the manipulations with the truth."

"There were lies from the very start," he said. "It is still unclear why the plane which should have pulled up and gone to another airport instead crashed into thousands of pieces."

In the "Smolensk" movie's official trailer, the plane explodes in a ball of fire and it suggests that there was a conspiracy. The film is based on findings by a party commission whose experts say there was an explosion before the crash.

President Andrzej Duda, who hails from Kaczynski's party, Prime Minister Beata Szydlo and Jaroslaw Kaczynski attended the premiere at Warsaw's National Opera House.