“The report makes a mockery of Poland,” Kaczynski told reporters after Russian investigators in Moscow presented their findings earlier Wednesday blaming the crew and other occupants of the presidential plane.

“This is the result of leaving the investigation in the hands of the Russians,” Kaczynski, who is also the leader of Poland’s conservative opposition, said.

“The report blames Polish pilots and Poland without proof in a unilateral fashion. Many questions remain unanswered,” he added.

“I didn’t hear anything today that would rule out or confirm the hypothesis of an assassination,” Kaczynski remarked. Conspiracy theories that a plot was behind the crash have circulated among Kaczynski supporters.

Russian investigators on Wednesday blamed Polish failures for the plane crash that killed Lech Kaczynski, revealing that top officials put pressure on inexperienced pilots to land in dangerous weather.

Poland’s Interior Minister Jerzy Miller however downplayed Jaroslaw Kaczynski’s sharp comments, saying Warsaw accepted the Russian report but that it was not without flaws.

“We are not disputing the criticism of the MAK (Russian investigators) towards the Polish side,” Miller told reporters in Warsaw.

“We would have made the same criticisms, it’s obvious to us.”

However, the Polish minister also blamed Russian air traffic controllers on the ground at the remote and rudimentary airport in Smolensk.

“Both (the Polish and Russian) sides were equally ill-prepared for the flight,” Miller said, adding Poland believed the Russian findings were incomplete.

Meanwhile, Senior Polish crash investigator Edmund Klich accused Tatiana Anodina, who steered the Russian probe, of “lying about free access for Polish experts to all the activities in the investigation.”

Lech Kaczynski died with 95 others when his presidential jet crashed on April 10, 2010, as it attempted to land in thick fog near the city of Smolensk in northwestern Russia, ahead of a high-profile World War II memorial ceremony.

In a damning report listing Polish shortcomings that risks sparking new tensions with Warsaw, the Russian probe included audio evidence that two senior Polish officials entered the cockpit to pressure pilots to land the plane as they did not want to annoy the president.

Anodina also said the Polish pilots had lacked sufficient training and ignored repeated advice from air traffic control to land elsewhere.

“The presence in the cockpit of high-ranking officials — Poland’s air force chief and head of protocol — and the expected negative reaction from the main passenger put psychological pressure on crew and affected decision-making regarding the continuation of landing under any conditions,” she said.

She did not identify the “main passenger” but it appears she was referring to Kaczynski. However, the commission emphasised that no comment from Kaczynski himself ordering the plane to land was found on the black box recording.

A spokesman for Poland’s Prime Minister Donald Tusk said he would cut short a holiday in Italy to return to Warsaw for consultations on the Russian report on Thursday.