The head of the Polish Senate has urged the country's government to drop its threat to veto the EU's budget, warning that it could lead to Poland's exit from the EU.
In a highly unusual address carried by all the major broadcasters, Tomasz Grodzki said a veto would undermine Poland's "economic, political and strategic interests".
"It is contrary to the good of our country," said Mr Grodzki, who is from the opposition Civic Platform party and who spoke with the Polish and European Union flags behind him.
"If you cause Poland to lose huge amounts of money for further development and reconstruction and if you lead us out of our European home, history and the people will not forgive you," he said.
Poland and Hungary have sparked a crisis in the bloc by threatening to veto proposals for its long-term budget and a coronavirus recovery package.
The two countries, both of which have been accused by Brussels of falling short of democratic norms, are opposed to rule of law conditions being attached to the funds.
Some opposition politicians in Poland are warning that the government's rhetoric could lead to Poland exiting the bloc, dubbing this a potential 'Polexit'.
"The government has no mandate to lead us out of the EU without asking the people for their opinion," Mr Grodzki said, adding: "Our deepest interest is a sovereign, law-abiding Poland in the centre of a united Europe."