On December 13, 1981, strongman Gen. Wojciech Jaruzelski declared martial law in an attempt to suppress mounting opposition to his communist regime, marking a dark chapter in modern Polish history.
The crackdown on the Solidarity freedom movement saw thousands of activists imprisoned and dozens killed.
In a ceremony at a Warsaw museum in the morning, officials paid tribute to communist-era political prisoners and others who faced brutal repression under communism.
Religious services and a host of other tributes were held throughout the day at various sites to honour the victims of the communist-era crackdown.
One of the tributes, led by Warsaw Mayor Rafał Trzaskowski and former president and Solidarity leader Lech Wałęsa, was for Grzegorz Przemyk, a high school student who was beaten to death by communist police in May 1983.
Officials and members of the public also honoured Jerzy Popiełuszko, a Roman Catholic priest who was killed by communist secret police in the 1980s, state news agency PAP reported.
In a closing tribute, many Poles lit candles in the windows of their homes in a symbolic gesture to commemorate the victims of communist oppression, according to media report.
The nationwide "Light of Freedom" tribute, attended by President Andrzej Duda, was held at Piłsudski Square in central Warsaw at 7:30 p.m.
According to a parliamentary report compiled in the early 1990s, more than 90 people were killed during martial law, which formally ended on July 22, 1983.
On the night martial law was declared, over 6,500 opposition activists were arrested and interned.
The communist regime also suspended political and workers' organisations and imposed a curfew.
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Source: IAR, PAP/PAP