Poland is to withdraw from a European treaty aimed at preventing violence against women, the country's justice minister announced on Saturday.

Zbigniew Ziobro said the document, known as the Istanbul Convention, was "harmful" because it required schools to teach children about gender.

He added that reforms introduced in the country in recent years provided sufficient protection for women.

Thousands of women have protested at the move in cities across Poland.

Mr. Ziobro said the government would formally begin the process of withdrawing from the treaty, which was ratified in 2015, on Monday.

He argued that the convention violated the rights of parents and "contains elements of an ideological nature".

The ruling Law and Justice (PiS) party and its coalition partners are closely aligned to the Catholic Church, and the government has promised to promote traditional family values.

President Andrzej Duda was re-elected earlier this month following a campaign in which he described the promotion of LGBT rights as an "ideology" more destructive than communism.

Thousands of people, mostly women, took to the streets of the capital Warsaw on Friday to campaign against the withdrawal from the Istanbul Convention.

"The aim is to legalize domestic violence," Marta Lempert, an organizer of a march in the city, told Reuters news agency.