BUCHAREST, Romania — The pro-European Union candidate in Romania’s tense presidential runoff has taken a lead in the polls, preliminary electoral data shows, in a closely watched vote against a hard-right nationalist that could determine the geopolitical direction of the NATO member country.

The race pits front-runner George Simion, the 38-year-old leader of the hard-right Alliance for the Unity of Romanians against Bucharest Mayor Nicusor Dan.

After 6.8 million votes had been counted, Dan was ahead with 52.4%, while Simion received 47.6%, according to official data.

Thousands gathered outside Dan’s headquarters near Bucharest City Hall to await the final results, chanting “Nicusor!” Each time his lead widened, the crowd, many waving the flags of Europe, would erupt in cheers.

When voting closed at 9 p.m. local time, 11.6 million people — about 64% of eligible voters — had cast ballots, according to official electoral data. About 1.64 million Romanians abroad, who have been able to vote since Friday at special polling stations, participated in the vote.

After polls closed Sunday, Dan told the media that “elections are not about politicians” but about communities and that in Sunday’s vote, “a community of Romanians has won, a community that wants a profound change in Romania.”

“When Romania goes through difficult times, let us remember the strength of this Romanian society. There is also a community that lost today’s elections. A community that is rightly outraged by the way politics has been conducted in Romania up to now.”

Turnout was significantly higher in the runoff and is expected to play a decisive role in the outcome. In the first round on May 4, final turnout stood at 9.5 million, or 53% of eligible voters.

Romania’s political landscape was upended last year when a top court voided the previous election in which far-right outsider Calin Georgescu topped first-round polls, citing allegations of electoral violations and Russian interference, which Moscow denied.

Standing on the steps of Romania’s colossal Communist-era parliament building after polls closed, Simion predicted a significant victory over his opponent, which he called a “victory of the Romanian people.” Simion said Georgescu was “supposed to be the president” before last year’s election was annulled.

He also called for vigilance against election fraud but said that overall he was satisfied with the conduct of the vote.

Shortly after 6 p.m., Romania’s Ministry of Foreign Affairs spokesperson Andrei Tarnea said in a post on X that the election was subject to a “viral campaign of fake news” on the Telegram messaging app and other social media platforms, which tried to influence the electoral process and had “the hallmarks of Russian interference.”

Years of endemic corruption and growing anger toward Romania’s political establishment have fueled a surge in support for anti-establishment and hard-right figures, reflecting a broader pattern across Europe. Simion and Dan have made their political careers railing against Romania’s old political class.

Simion’s critics say Simion is a pro-Russia extremist who threatens Romania’s longstanding alliances in the EU and NATO.

Most recent local surveys indicated that the runoff would be tight; earlier ones showed Simion holding a lead over Dan, a 55-year-old mathematician who rose to prominence as a civic activist fighting against illegal real estate projects.

Dan founded the reformist Save Romania Union party in 2016, but later left, and is running independently on a pro-European Union ticket reaffirming Western ties, support for Ukraine and fiscal reform.

The president is elected for a five-year term. The winner of Sunday’s race will be charged with nominating a new prime minister.