By Adam Easton
BBC News, Warsaw
A gay tolerance march in the southern Polish city of Krakow has been attacked by a rival demonstration of young nationalists.
Gay activists in Poland say they suffer discrimination
Police using riot shields and batons kept the two demonstrations apart.
Several arrests were made after members of the far-right All Poland Youth Group began throwing stones and eggs at the participants of the tolerance march.
More than 1,000 people, including an ex-deputy PM, took part in the march to promote tolerance to gays and lesbians.
At the same time, activists from the nationalist All Poland Youth were holding what they called a "tradition" march.
Some held banners daubed with the words, "Stop deviation". Others chanted, "Lesbians and gays, all of Poland is laughing at you".
The tolerance demonstration changed its route to avoid a clash, but some members of the tradition march ran after it, hurling stones and eggs.
Two years ago, a gay march in Krakow was also attacked.
Homophobia is not uncommon in this staunchly Catholic country.
And gay rights groups say the situation has deteriorated since the conservative Law and Justice Party came to power last September.
It campaigned on traditional, family and Catholic values.
Shortly after he became Prime Minister, Kazimierz Marcinkiewicz said in an interview that homosexuality is unnatural.
According to surveys, nine out of 10 Poles agree with him.