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, Reuters reported.

Ciolacu said his centre-left Socialists would withdraw from the pro-Western coalition - effectively ending it - while cabinet ministers will stay on in an interim capacity until a new majority emerges after the presidential run-off.

Hard-right eurosceptic George Simion decisively swept the ballot on Sunday, with some 41% of votes, and will face Bucharest mayor Nicusor Dan, an independent centrist, in a May 18 run-off. Coalition candidate Crin Antonescu came third.

Although Ciolacu's leftist Social Democrats (PSD) won the most seats in a Dec. 1 parliamentary election, Simion's AUR and two other far-right groupings, one with overt pro-Russian sympathies, won more than a third of the seats to become a clear political force, according to Reuters.