Tens of thousands of Polish protesters took to the streets on Tuesday, to mark 35 years since a Communist-era martial law crackdown, while accusing the current rightwing government of undermining democracy.
In Warsaw, demonstrators gathered in front of the former headquarters of the communist Polish United Workers' Party, and then marched to the ruling Law and Justice (PiS) party building.
"Today, just like 35 years ago, the government is attacking us, and depriving us of our freedom," said Mateusz Kijowski, leader of the KOD pro-democracy movement.
"Today, we must all stand together. Solidarity is what unites us today, just as it did in the past."
The demonstrators paid homage to the victims of a crackdown that followed the imposition of martial law on December 13, 1981, by General Wojciech Jaruzelski.
Meanwhile the PiS held its own event to commemorate the 1981 martial law announcement. Several thousand people took part in the rival event.
PiS leader Jaroslaw Kaczynski criticised the opposition "for trying to compare the current government with the one from that era; the return to order in Poland to martial law".
He also said Poland had now become "the European nation with the most liberties".
The Polish opposition has condemned the government for pushing through Constitutional Court reforms that critics say were intended to paralyse the institution.
The reforms have notably alarmed the European Union and triggered a string of demonstrations in Poland in recent months.
The PiS party swept back into power in late 2015 after nearly a decade, playing on fears sparked by the refugee influx.
Kaczynski has said refugees bring "cholera to the Greek islands, dysentery to Vienna, various types of parasites".