President Lech Kaczyński, his wife and dozens of top political and military figures died when a Polish plane carrying them crashed near Smolensk, western Russia, on April 10, 2010.
The event is commemorated every month in Warsaw with ceremonies including a religious service.
Monday’s observances began with a Catholic Mass attended by Poland's ruling party chief Jarosław Kaczyński, twin brother of the late president, and other prominent conservative politicians, among them Prime Minister Mateusz Morawiecki.
Later in the day, officials laid flowers at a recently unveiled statue commemorating the late President Lech Kaczyński in central Warsaw and at a separate monument unveiled in April to honour all 96 victims of the fatal 2010 Polish presidential plane crash in Russia, the PAP news agency reported.
Those taking part in Monday’s commemorations included former Defence Minister Antoni Macierewicz, who in February 2016 appointed a new team of investigators to look into the disaster.
Reinvestigation in progress
The ruling conservative Law and Justice (PiS) party has long challenged an official report into the 2010 crash issued by Poland’s previous government, which cited a catalogue of errors on the Polish side, while also pointing to errors made by Russian staff at the control tower of Smolensk Military Airport.
A Russian report placed all the blame on the Poles.
Law and Justice has launched its own inquiry into the crash which, in initial findings, suggested the plane was probably destroyed by a mid-air explosion, and that Russian air traffic controllers deliberately misled the Polish pilots about their location as the presidential plane approached the runway of the Smolensk military airport in 2010.
In mid-December last year, Macierewicz said that Russia was responsible for the plane crash. He also said that the Polish presidential plane was destroyed by "two explosions."
In January, the new team of investigators appointed by Macierewicz said that the jet’s left wing was destroyed as a result of an explosion on board.
The commission said that the explosion had “several sources” on the plane.
In early February, around-the-clock channel Sky News reported that a British air accident investigator had told it he believed there were explosions on board the Polish president’s plane before its fatal crash in 2010.
On April 10, Jarosław Kaczyński led the 96th and, as he said, the last monthly March of Remembrance for the crash victims through the Polish capital’s Old Town district following a memorial mass at the local St. John's Cathedral.
The Parliamentary Assembly of the Council of Europe in October adopted a resolution calling on Moscow to return the wreckage of the Polish presidential plane.