Poland's socially conservative Law and Justice party (PiS) claimed a landslide victory on Sunday.

According to Reuters, PiS secured enough of the vote to govern alone.

PiS is run by Jaroslaw Kaczynski, the twin brother of Poland's late president Lech Kaczynski, who died in a plane crash in 2010.

Lech Kaczynski's clashes with Polish gay rights activists gained him international notoriety. As mayor of Warsaw, he repeatedly banned gay pride parades from taking place in the city, citing security concerns and an offense to public morals.

Jaroslaw Kaczynski once stated that gay rights would lead to the downfall of society.

“The affirmation of homosexuality will lead to the downfall of civilization,” he said. “We can't agree to it.”

PiS has vowed to use Roman Catholic values to guide its lawmaking and is opposed to LGBT rights.

On the campaign trail, Kaczynski and other PiS leaders stressed their opposition to Muslim migrants.