Portugal’s third general election in three years has failed to deliver the result that could break the worst spell of political instability for decades in the European Union country of 10.6 million people.

Romanian, Portuguese and Polish nationals have been casting their ballots, with millions of Europeans taking to the polls on Sunday.

Nationalism remains the defining matter of European politics as these elections have presented referendums on the populist movements gaining traction in the Old World.

Portugal's ruling centre-right Democratic Alliance (AD) took an early lead in Sunday's parliamentary election, garnering over 38% of the vote with more than 10% of the ballots counted, official electoral data showed.

Romanian, Portuguese and Polish nationals have been casting their ballots, with millions of Europeans taking to the polls on Sunday.

Portugal’s president will start Tuesday to convene the country’s political parties for consultations, after a general election delivered another minority government as well as an unprecedented showing by populist party Chega (Enough) that added momentum to Europe’s shift to the far-right.

Voters in Portugal are returning to the polls for a third general election in three years, as the country’s increasingly fragmented political landscape defies efforts to unite behind policies on pressing national issues such as immigration,

Incumbent Portuguese Prime Minister Luis Montenegro and Socialist party leader Pedro Nuno Santos cast their votes on Sunday in Portugal's general election. Voters are returning to the polls for a third general election in three years,