Poland has honored thousands of anti-communist fighters persecuted and killed during the early years of the Soviet-imposed regime, which also ignored their existence in history books for decades.

Tuesday's nationwide observances, led by President Andrzej Duda, are part of democratic Poland's efforts to recognize the sacrifice of men and women who actively opposed the communist regime, which seized power after World War II. The fighters were a taboo topic under communism.

State officials and families of the fighters were attending wreath-laying ceremonies, prayers and other observances in Warsaw and elsewhere.

With little written record of communist crimes, historians can only roughly estimate the number of those killed at between 8,600 and over 25,000. They mostly were recruited from the wartime resistance that fought against the brutal German occupation of Poland.