A top Romanian court has validated the first round of a presidential race in which a far-right outsider emerged as the frontrunner, plunging the country into a week of turmoil amid allegations of electoral violations and Russian meddling.

Romania's Constitutional Court on Monday validated the shock first-round result in its presidential election, setting the stage for a run-off vote on Dec. 8 that could upend the country's pro-Western orientation and erode backing for Ukraine.

Romanian centrist and leftist parties looked to have fended off a surge by the nationalist right in Sunday's parliamentary election, as attention turned to a top court ruling later on Monday on whether to annul the results of a presidential vote.

Romanians cast ballots Sunday in a parliamentary election sandwiched between a two-round presidential race, the first of which has plunged the European Union and NATO member into unprecedented turmoil following allegations of electoral violations and Russian interference.

The leftist Social Democratic Party topped the polls in Sunday's vote and the far-right nationalist Alliance for the Unity of Romanians came in second.

Romania's ruling leftist Social Democrats (PSD) looked set to win the most votes in a parliamentary election on Sunday, fending off a resurgent far-right movement that challenges the country's pro-Western orientation,

Romania's ruling center-left Social Democrats were poised to secure the most votes in Sunday's parliamentary election, according to preliminary results published Monday.