Hungarian Prime Minister Viktor Orban on Sunday conceded defeat to opposition leader Peter Magyar in what he called a “painful” election result, ending his 16 years in power in a setback for his allies in Russia and U.S. President Donald Trump’s White House.

Results based on 46% of votes counted showed the centre-right, pro-EU Tisza party of Peter Magyar winning 135 seats - or a crucial two-thirds majority - in the 199-member parliament, ahead of Orban's Fidesz party.

"The election results, though not yet final, are clear and understandable; for us, they are painful but unambiguous," said Orban at the Fidesz campaign offices.

"We have not been entrusted with the responsibility and opportunity to govern. I congratulated the winning party. We are going to serve the Hungarian nation and our homeland from opposition as well."

Magyar posted on Facebook that "Prime Minister Viktor Orbán just congratulated me on the phone on our victory."