President Andrzej Duda said in a message on Friday that the fighters, referred to by some as the “Cursed Soldiers” and by others as "Enduring Soldiers," "paid for their steadfastness with imprisonment, torture, death and condemnation to oblivion."
Duda added: "I would like to thank our wonderful heroes ... I would also like to thank all those who preserve and nurture the memory of them."
The office of Prime Minister Donald Tusk said the "Cursed Soldiers" fought against the communist dictatorship after the end of WWII.
It added that many of the fighters "were thrown into prisons, where they were tortured and murdered."
Meanwhile, Deputy Prime Minister and Defence Minister Władysław Kosiniak-Kamysz honoured the memory of the fighters at Warsaw's Military Powązki Cemetery, Polish state news agency PAP reported.
More tributes were set for later in the day, with Duda expected to take part in a wreath-laying ceremony in the northeastern town of Mława.
After Poland's official underground army (AK) of World War II disbanded, thousands of Poles continued to fight in other formations as the Soviet Red Army extended its grip across the country.
The “Cursed Soldiers” faced a brutal crackdown by Poland’s communist authorities and were a taboo subject during the country’s decades under communist rule.
The fighters were largely stamped out by 1948, although one, Józef Franczak, was gunned down as late as 1963.
An official day of remembrance for the fighters was introduced in 2011, more than two decades after the fall of the Iron Curtain.
March 1 was selected as a poignant date for the day of remembrance, as on this day in 1951, seven prominent members of a postwar resistance force called Freedom and Independence were executed in Warsaw.
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Source: IAR, PAP