WARSAW, Poland (AP) — Hundreds of thousands of people marched in an anti-government protest in Poland’s capital on Sunday, with citizens travelling from across the country to voice their anger at officials who they say have eroded democratic norms and created fears that the nation is following Hungary and Turkey down the path to autocracy.

Warsaw Mayor Rafal Trzaskowski, who belongs to the opposition party that led the march, estimated that 500,000 people took part. The Onet news portal estimated there were at least 300,000 at the march’s culmination.

Large crowds also gathered in Krakow and other cities across the nation of 38 million people, showing frustration with a government that critics accuse of violating the constitution and eroding fundamental rights in Poland.

Former President Lech Walesa, the leader of the Solidarity movement that played a historic role in toppling communism in Poland, marched alongside the leader of the opposition Civic Platform party, ex-Prime Minister Donald Tusk.

Walesa and Tusk are reviled by the ruling Law and Justice party led by Jaroslaw Kaczynski, and the Warsaw crowd chanted “Democracy!” and “Constitution!”

The rally started at Prime Minister Mateusz Morawiecki’s office and ended at the Royal Castle, where Tusk hailed the turnout and pledged to fight to win an autumn election.

“We are going to these elections to win and to right human wrongs. I promise you victory, a settlement of evil, compensation for human wrongs and reconciliation among Poles,” Tusk told the crowd.

The government spokesman, Piotr Mueller, accused Tusk and Walesa of “trying to overthrow the government.”

Tusk had called on Poles to march with him for the sake of the nation’s future — a message that resonated for Radek Tusinski, 49, who arrived with his wife and two children. A handmade sign reading “I cannot give up freedom” was attached to their baby stroller.

Tuskinski said that he worries about the creeping return of an authoritarian system similar to what he remembers from his childhood.

“We want a free country for our children,” he said.

Supporters of the march have warned that the election might be the nation’s last chance to stop the erosion of democracy under Law and Justice amid growing fears that the fall election might not be fair.

In power since 2015, Law and Justice has found a popular formula, combining higher social spending with socially conservative policies and support for the church in the mostly Catholic nation.