The marchers at the first gay pride parade here in the conservative Polish city of Bialystok expected that they would be met with resistance.

But last week when Katarzyna Sztop-Rutkowska saw the angry mob of thousands that awaited the marchers, who numbered only a few hundred, she was shocked.

“The most aggressive were the football hooligans, but they were joined by normal people — people with families, people with small children, elderly people,” she said.

They blocked her way, first hurling invective, then bricks and stones and fireworks, she said. From the balconies, people threw eggs and rotten vegetables. Even before the march started, there were violent confrontations, and by the time the tear gas cleared and the crowd dispersed, dozens were injured and Poland was left reeling. Much as the racist violence in Charlottesville, Va., shocked the conscience of America, the brutality in Bialystok last week has rocked many in Poland and raised grave concerns over a steady diet of anti-gay political propaganda in the country.

In a show of solidarity with the L.G.B.T. community in Bialystok, thousands of demonstrators took to the streets of Warsaw and other cities around the country on Saturday. They carried rainbow flags and vowed to combat intolerance.

“One week ago, the government betrayed the people in Bialystok, gays and lesbians,” said Pawel Rabiej, the openly gay deputy mayor of Warsaw. “Warsaw is for everyone and so should the rest of Poland. Solidarity will conquer the time of contempt.”

Since this spring, when the governing Law and Justice Party stepped up its anti-L.G.B.T. language in advance of European Parliament elections, the language has only grown more heated as national elections approach this fall. Read more via NYT