(Bloomberg) -- Poles took to the streets of Warsaw in droves on Sunday to show their support for the opposition ahead of what’s expected to be a tightly contested parliamentary election in October.

Hundreds of thousands joined the march, which was convened by former European Council President Donald Tusk to coincide with the anniversary of the first, partially free elections in the former Soviet bloc in 1989. Some waved national and European Union flags, while others held placards calling for a free and fair vote.

The ruling Law & Justice party has been criticized by the EU for eroding democratic standards in the bloc’s sixth-biggest economy by undermining the independence of courts, the free media and LGBTQ rights. It’s now facing a challenge to its two-term rule as opinion polls show the party may struggle to hold on to its parliamentary majority.

Protests gathered steam in the last few days after the ruling party adopted a controversial law that would allow for an inquiry into Tusk and other opposition politicians over alleged Russian meddling. The EU and the US have criticized the legislation and President Andrzej Duda on Friday proposed amending it — five days after signing it into law.

“I’ve had enough of looking at this circus, this demolition of democracy in Poland,” said Bartlomiej Ficner, 30, who came from Wroclaw, western Poland, where he runs a small IT business. “What’s happening isn’t normal and we’re here to protest that.”

The ruling party sparked an outcry last week by posting a video on social media that used images from the Nazi Auschwitz concentration camp to discourage people from attending the march. The website of the state television’s main news channel on Sunday showed limited coverage of the event under a headline “The March of Hatred.”

“We’re here today to show all of Poland, the entire European Union and the world how strong we are,” Tusk told the crowds at the beginning of the march. “Nothing is going to stop this voice, this wave. The giant has awakened.”

Tusk was accompanied by the former leader of the Solidarity trade union and a Nobel Peace Prize winner Lech Walesa. 

A government spokesman, Piotr Muller, wrote on his Twitter account that Tusk and Walesa are trying to overthrow the ruling cabinet.

About 500,000 people joined the march, according to preliminary estimates by Warsaw’s municipal authorities, although several ruling-party politicians including EU Affairs Minister Szymon Szynkowski vel Sek said the turnout was much lower. Crowds stretched along the 2.9-mile route in downtown Warsaw, spilling into side streets.

“I’d like to live in a democracy, where the rule of law matters,” said Anna Dzikowska, a pensioner who came to Warsaw from the Swietokrzyskie region of southern Poland.“I’m here to say that I want things to be normal again.”

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