Thursday marked 88 months since a Polish plane carrying President Lech Kaczyński, his wife and 94 others – including top political and military figures – crashed near Smolensk, western Russia.
The event is commemorated monthly in Warsaw with a Catholic Mass and a procession to the Presidential Palace.
But anti-government protesters have in the past brushed with marchers, largely supporters of the conservative Law and Justice (PiS) government.
Monuments to victims
Jarosław Kaczyński, the leader of the Law and Justice party and twin brother of the late president, on Thursday said that the monthly marches would continue until monuments to the Smolensk disaster victims are erected in Warsaw.
"I believe that monuments will be erected here on the eighth anniversary [of the April 10, 2010 crash] and that we will hear the final answer about the Smolensk disaster," Kaczyński said, addressing those gathered.
He implied that the monthly tributes would go on until a total of 96 marches have been held to honour all 96 victims of the crash.
Ahead of the commemorations, Poland's Interior Minister Mariusz Błaszczak declared that police would ensure security for all those taking part in the march, while his deputy Jarosław Zieliński asked PiS's political opponents to allow legal public gatherings to take place uninterrupted.
Like a month earlier, an anti-government protest was held nearby despite a ban issued by the province governor.
The protesters did not clash with the marchers, but there were unofficial reports of police intervention after the commemorations. Details were not immediately available.
A spokesman for the Warsaw police, Sylwester Marczak, told the PAP news agency that about 2,000 police officers had been deployed to provide security during "all the assemblies" in Warsaw on Thursday.
In June, anti-government protesters sat along the width of Warsaw's Krakowskie Przedmieście street, blocking the March of Remembrance's route. Some of the protesters were forcibly moved by police.
PiS has long challenged an official report into the crash issued by the previous Polish 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.
PiS 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 Polish pilots about their location as the presidential plane approached the runway of the Smolensk military airport in 2010. (str/pk)