George Simion, a nationalist and vocal supporter of U.S. President Donald Trump, has won Romania’s first-round presidential election after capitalizing on widespread anti-establishment sentiment.

The leader of the Alliance for the Union of Romanians will now face off against centrist mayor of Bucharest, Nicusor Dan. The run-off vote is set for May 18.

Romanian Prime Minister Marcel Ciolacu resigned on Monday, a day after a far-right opposition leader won the first round of the presidential election re-run and his own candidate crashed out of the race.