Polish nationalists staged a rally in front of the Russian embassy in Warsaw on Sunday on the eve of the 2nd anniversary of the plane crash in which president Lech Kaczynski died along with 95 other people including his wife.
They are highly critical of the Russian handling of the investigation into the crash, and of Polish Prime Minister Donald Tusk for accepting its finding.
The events surrounding the crash have divided the country.
The investigation into the accident was carried out by the Russians because it happened on their territory.
The report blamed the pilots’ decision to attempt to land despite extremely poor visibility caused by dense fog at the airfield in Smolensk.
The official commemorations begin on Tuesday. Last year they were boycotted by Lech Kaczynski’s twin brother Jaroslaw, who is leader of the main oppostion party in Poland.