ISTANBUL

Polish Prime Minister Donald Tusk vowed Thursday to deliver a "ruthless" response to any attempt by newly sworn-in conservative President Karol Nawrocki to interfere in his government’s work, according to media reports.

"Wherever he wants to interfere, he will see what the constitutional rule is all about, that is, who governs in the country, and I will be very consistent in this matter, and if necessary, also ruthless," Tusk said at a news conference, broadcaster TVP World reported.

He reaffirmed that he would welcome any cooperation from Nawrocki with "open arms," underlining that anyone who wants to help is a "welcoming partner."

Nawrocki’s inauguration ceremony was held in front of parliament on Wednesday, as he succeeded Andrzej Duda, who had served since 2015.

He won the presidential election with 50.9% of the vote, narrowly defeating Warsaw Mayor Rafal Trzaskowski in a fiercely contested June 1 runoff.

Nawrocki’s tenure as a 42-year-old conservative historian may strain Poland’s EU relations due to his Eurosceptic stance, close ties with the Trump administration and his focus on national priorities, such as favoring Polish citizens over Ukrainian refugees in economic and social policies.

Nawrocki’s election also signals a nationalist shift in Poland, aligning with broader right-wing populist trends in Europe.

Backed by the right-wing opposition Law and Justice (PiS) party, which supported Duda, Nawrocki is expected to use his veto powers to block the government's plans to ease abortion access and undo legal changes introduced by PiS between 2015 and 2023.

The election is seen as a setback for Tusk’s broad coalition, spanning from the left to the center-right.