Two former Polish presidents have led tens of thousands of marchers in Warsaw to protest against the right-wing government's policies and mark 27 years since the fall of communism.

The march on Saturday was yet another in a series organised by a new civic movement, the Committee for the Defence of Democracy, or KOD, against the conservative government that took office in November.

The government's policies have strained Poland's relations with the European Union and the United States and angered many in Poland. But the ruling party insists it has a mandate from Poland's voters.

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The nationalist government has focused on helping those left out of Poland's economic growth and increased its grip on state institutions.

The moves have paralysed the nation's Constitutional Tribunal, put state-owned media under government control and increased police surveillance powers.

The EU says Poland's rule of law and democracy are in danger.

The protests on Saturday brought former presidents Aleksander Kwasniewski, a left-winger, and Bronislaw Komorowski, a centrist, together to remind the Poles about their attachment to freedom and to democracy, which they won on June 4, 1989, in an election that peacefully dislodged the communists from power.

"We want a free Poland because we fought for it, we dreamed about it and we built it," Komorowski, a dissident under communism, told the crowd.

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Warsaw authorities said that 50,000 people took part. Smaller marches also took place in other Polish cities and in Berlin and Brussels.

Marchers chanted "Freedom, equality, democracy!" and carried Polish and European flags.

"We want to live in a democratic country. We want to express ourselves," a protester at the march in the Polish capital told Al Jazeera. "We want people to say what they want to say and do what they want to do."

At the ruling Law and Justice party's regional meeting in Warsaw, party leader Jaroslaw Kaczynski insisted on Saturday that his policies are improving the lives of Poles and protecting Poland's independence in the 28-nation EU.

Poles have the right to "a new, better shape [of Poland] that would better serve the vast majority of Poles and we will not give that right up," Kaczynski said, pounding the podium.