More than 1,000 people took part in a pride parade in the Polish town of Plock, protected by a string of armed police, while LGBT rights became a major issue in Catholic Poland before the October parliamentary elections.
Poland's Party of Law and Justice (PiS) has made hostility to gays a central focus of its campaign, portraying LGBT rights as a dangerous foreign idea that undermines traditional values.
A pride parade in the provincial town of Bialystok in July was marred by violence after anti-gay protesters chased people down the streets and beat them.
Critics say PiS has fueled anti-gay sentiment and helped lead violence against the LGBT community in Poland.
Protesters walked the streets of Plock waving rainbow flags as they were surrounded by riot troops, TV images from private TVN showed.
Politicians, including Robert Biedron, one of Poland's first openly gay politicians who launched the leftist Wiosna party earlier this year, took part in the march.
A group of counter-protesters gathered at the Plock parade and shouted homophobic insults, but was prevented from interacting with parade participants by the heavy police presence.
A Plock police spokeswoman told Reuters that there were about 950 counter-protesters in total and that two people were detained.
There were no serious incidents, the spokeswoman added, although there were some fights with the police, according to TV images.
“For many years in Poland, little has been done to deal with this violence. It's time for these hate crimes to be punished, ”Biedron said in a pre-march speech broadcast on TVN.
PiS maintained steady support in the polls before the October 13 vote, despite a recent scandal in which the former President of the Polish Parliament used government aircraft for private travel.
Analysts say PiS's criticism of LGBT rights could be a strategy for mobilizing its conservative rural base.
If parliamentary elections were to take place on Sunday, 43% of Poles would vote for PiS, said the poll, conducted between 6 and 7 in August.
The opposition civic coalition would accumulate 28%, while a left-wing bloc of three parties, including progressive Wiosna, would gain 12%.
Members of the Polish Catholic Church, seen as a close ally of PiS, have also criticized LGBT rights in recent weeks.
Marek Jedraszewski, one of Poland's senior Catholics, earlier this month compared gay rights activists to former communist leaders in Poland in a sermon to mark the 75 anniversary of the Warsaw Uprising.
On Saturday, about 3,000 people gathered in Krakow to express support for Jedraszewski, a Krakow police spokesman told Reuters.
Senior members of the PiS parliament, including the vice-presidents of the Senate and Parliament, were among those praying outside the Cracow Curia, private radio station Radio Zet said.
Earlier this week, hundreds of people gathered in Warsaw in front of the apostolic nunciature to protest Jedraszewski's comments and demand his resignation.