The crash report admitted most of the blame for the disaster in which all 96 people on board were killed lay with Poland, but it also listed a number of shortcomings by Russia where the plane went down.

“The flight crew of the airplane in question was not sufficiently prepared for the task at hand given the complexity of the situation the crew encountered during their last flight,” the 328-page report said.

“The aircraft commander, co-pilot, and navigator had been trained hastily, haphazardly, and in violation of the respective training regulations,” it added.

The report describes at length how the flight, in which Kaczynski’s wife and many other high-profile Poles died, was badly prepared.

The doomed flight’s military crew had not received appropriate training, the navigator’s Russian was weak, and the meteorological information was incomplete, the report said.

The report mentions the “crew’s improper preparation for the flight… presence of third parties in the cockpit, lack of the crew’s effective cooperation, accepting too many responsibilities by the aircraft commander, insufficient level of the crew’s training.”

In its own crash report released in January, Russia had put the blame squarely on the Poles for the crash, arguing that the pilots brought about the tragedy by insisting on landing in fog.

But the Polish report found some shortcomings on the Russian side too, emphasising that the lighting at Smolensk North airport was inadequate as were instructions given by Russian air traffic controllers.

“The condition of the lighting system was incompatible with the specifications required of visual navaids,” the report said.

The inquiry commission’s findings also said that the terrain immediately ahead of the runway “was overgrown with trees which were taller than the permissible height of terrain obstacles in that area.”

The Russian report had led to blame-trading between Warsaw and Moscow, with Polish Prime Minister Donald Tusk faulting the Russian findings.

A Polish government report on the crash is due to be released later this week.

Poland’s conservative Law and Justice party — led by Jaroslaw Kaczynski the late president’s twin brother — has accused Tusk’s centre-right government of failing to take Russia to task.

A Law and Justice-run parliamentary commission is also probing the crash.

Last month, the commission’s leader Antoni Macierewicz blamed Russia squarely, claiming it had forged the testimony of Smolensk’s air traffic controllers, who he alleged had misled the pilots.

Adding an extra layer of sensitivity to the wrangling is the fact that the delegation had been bound for a memorial ceremony in nearby Katyn for thousands of Polish captives slain by the Soviet secret police in 1940, a massacre denied by the Kremlin until 1990.