WARSAW — The largest pride parade in central and Eastern Europe brought tens of thousands of people to the streets of Warsaw on Saturday, at a time when the gay rights movement in Poland is under siege by hate speech and a government campaign depicting it as a threat to families and society.

Diplomats from Canada, the United States and other Western nations continued a tradition of joining the Equality Parade to show their support for what is considered a basic human right in many places. Warsaw’s mayor, Rafal Trzaskowski, joined the parade for the first time.

“Not everyone has to go to the Equality Parade, but everyone should respect minority rights,” he told the crowd from a parade float. “It’s really important for me that Warsaw be open, that Warsaw be tolerant.”

While many Poles in Warsaw and other cities have grown increasingly supportive of the rights of lesbians, gay men and bisexual and transgender people, a backlash is underway. In recent months, officials from the right-wing governing party, Law and Justice, have portrayed the rights movement, particularly calls for sex education stressing tolerance, as a threat to families and children.