Poland's president on Wednesday swore in Donald Tusk as the new pro-EU prime minister, putting an end to eight years of right-wing populist rule.
Tusk, a veteran politician who already served as premier in the past, has pledged to restore Poland's position in the EU and to double down on efforts to provide more aid to neighbouring Ukraine.
The former European Council president is expected to travel to Brussels later on Wednesday to participate in the bloc's summit with fellow EU leaders.
Tusk's Civic Coalition together with two smaller political groups forged an alliance that ousted the Law and Justice (PiS) from power, winning backing in the parliament in a vote of confidence Tuesday.
"Our homeland is a place of political and civic miracles," Tusk said after his cabinet was sworn in during a ceremony in Warsaw.
He feted the record-high turnout of the October election that brought political change to the NATO member of 38 million people.
In his earlier keynote address to lawmakers, Tusk vowed to stand behind Ukraine "from day one" and denounced leaders "who speak of being fatigued by the Ukraine situation".
He also promised to unblock billions of euros in EU funds earmarked for Poland and withheld due to rule-of-law infringements by the previous government who frequently clashed with Brussels while being accused of violating the constitution by opposition at home.
After being appointed, Tusk referred to those tensions, pledging his government "will remain faithful to the provisions of the constitution".
Following the swearing-in ceremony, EU allies congratulated Tusk, with German Chancellor Olaf Scholz on Wednesday hailing his intention to "lead Poland back to the heart of the EU".
Poland's ties with Germany were also strained, with PiS playing an anti-German card in the run-up to the election and launching repeated verbal attacks on Tusk personally and at his party.
On Monday, PiS leader Jaroslaw Kaczynski accused Tusk in the parliament of being a "German agent".
The new government is likely to face daily battles with the PiS, who still has allies in the central bank and the supreme court, as well as in several important judicial and financial state institutions.
Polish President Andrzej Duda, also allied with the PiS, could potentially use blocking tactics to veto legislation drafted by the new coalition before his term ends in 2025.
But during the swearing-in ceremony Duda suggested he was open to cooperate with the new government.
Tusk's cabinet includes Radoslaw Sikorski as foreign minister -- a job he has held in the past -- as well as former ombudsman Adam Bodnar as justice minister.
The PiS won the most seats in October's general election but failed to find viable coalition partners and secure backing for their minority government on Monday.
While Tusk's Civic Coalition came second in the ballot but together with two pro-EU political groups, the Third Way and Left, garnered enough support to oust PiS.
