Warsaw’s liberal mayor Rafal Trzaskowski won a narrow victory in Poland’s presidential election, but a second-round run-off with conservative historian Karol Nawrocki will be required to decide the country’s next president.

The state electoral commission (PKW) said Trzaskowski, a deputy leader of prime minister Donald Tusk’s centrist Civic Platform (PO) party, won 31.3% of the vote.

Nawrocki came second with 29.5% of the vote.

Final official results are not expected until later on Monday. Turnout was over 67%.

Trzaskowski and Nawrocki are now set to compete in a second-round on 1 June as none of the 13 candidates won more than 50% of the vote.

Trzaskowski told his supporters at a rally in Sandomierz, southern Poland: “We’re going to win.” But he said a lot of work and “great determination” would be needed.

“I’m convinced that all Poland will win,” he said.

He pledged to cooperate with prime minister Tusk’s coalition to liberalise the country’s strict abortion law and accelerate reform of the Polish judiciary, which was widely seen to have been politicised by the previous PiS-led government.

Trzaskowski performed worse than opinion polls predicted before the vote, which had him between 4%-6% ahead of Nawrocki.

Poland’s president has largely ceremonial powers but he or she is able to veto government legislation. Tusk’s coalition does not have a big enough parliamentary majority to overturn a presidential veto.

Tusk has failed to deliver many of his campaign promises, partly because the incumbent conservative president Andrzej Duda has vetoed his government’s legislation, but also due to divisions within the coalition over issues like abortion and civil partnerships.

A victory for Trzaskowski would remove the president’s veto, but Nawrocki would likely be an even tougher obstacle than Duda.

Nawrocki told his supporters in Gdansk that Tusk must be stopped from winning total power in Poland.

He called on supporters of two far-right candidates, Slawomir Mentzen, who came third and won 14.8%, and of Grzegorz Braun, who came fourth and won 6.3%, to “save Poland” from Tusk.

A lot will depend on which candidate can mobilise their electorate in the second round.

Nawrocki was unknown on a national scale before Law and Justice (PiS) chose him as its candidate. But he has improved on the job, and PiS is traditionally good at getting their vote out.

Trzaskowski will need to win the votes of supporters of his centrist party, but also those supporting the candidates of the junior coalition partners, the Left (Magdalena Biejat) and conservative Third Way (Szymon Holownia).

Another worry for Trzaskowski is the better than expected result of far-right candidates because many of their supporters will not vote for him.

Mentzen’s result was a strong showing and continued the improvement of his far-right Confederation party since it entered parliament in 2019.

Who will his, mainly young voters, back in the run-off?

Many would support Nawrocki for his Catholic, family-oriented views, but they dislike PiS’s left-wing economic policy of generous state benefits.

Mentzen is an anti-establishment candidate, and some of his supporters may not want to vote for either Nawrocki or Trzaskowski, who represent the two parties that have dominated Polish politics for two decades.

Far-right MEP Grzegorz Braun’s result was a nasty surprise for Poland’s liberal voters.

Braun made headlines in 2023 when he put out the candles on a Jewish menorah in the Polish parliament with a fire extinguisher following a ceremony for the festival of Hanukkah.

Braun called the festival “satanic”. During a presidential debate last month he said: “Jews have far too much say in Polish affairs.”