Thousands of people are protesting in the Polish capital Warsaw as a constitutional crisis between the government and the top court deepens, according to BBC News.
The government wants to change the way the court works, but the court says the changes are unconstitutional.
The government has refused to publish the court's ruling because to do so would make it binding.
Critics say the changes would limit the court's ability to scrutinise government legislation.
Since it came to power last October, the new government of the conservative, populist Law and Justice party (PiS) has regularly clashed with the media and the opposition.
In Warsaw, demonstrators waving Polish and EU flags marched from the Constitutional Court to the presidential palace. Rallies also took place in the cities of Poznan and Wroclaw.
The government says the protests are proof that democracy is thriving in Poland. It argues that it won a strong mandate in elections last October to introduce sweeping reforms.