Romania’s main centre-left party was on track to finish first in parliamentary elections, according to preliminary results, seemingly beating an advancing far right boosted by the shock victory of an ultranationalist in last week’s presidential first-round ballot.

With 90% of votes counted, the ruling Social Democratic party (PSD) won 23.9% of the vote, ahead of the far-right nationalist Alliance for the Union of Romanians (AUR) on 17.9%, while the National Liberal party (PNL) had 14.6% and centre-right Save Romania Union (USR) 11.1%.

The vote was the second of three successive ballots and came a week after Călin Georgescu, a little-known far-right, Moscow-friendly independent, plunged the country into turmoil by finishing first in the opening round of the presidential vote.

Georgescu’s success, after a campaign that he said had no financing and that was based heavily on viral TikTok videos boosted by bot-like activity, raised suspicions of foreign interference and caused fears Romania would veer to the far right.

Romania’s top court ordered a recount and on Monday is due to rule on a request by a defeated candidate to annul the vote altogether over allegations of illegal electoral activity on behalf of the runner-up, Elena Lasconi of the pro-EU USR.

The elections are seen as critical to the future direction of Romania, hitherto a reliable EU and Nato ally that is strategically important for western support for Ukraine. It has largely evaded nationalism since emerging from communism in 1989.

Amid widespread voter anger over the cost of living and a legacy of corruption among its mainstream parties, observers had said the far right, led by the AUR, was likely to benefit most from the confusion, which has further dented trust in state institutions.

Romania has the EU’s biggest share of people at risk of poverty, the bloc’s highest inflation rate and its largest budget deficit.

Far-right parties have used Romania’s strong backing of Ukraine to stoke fears that the war could spill over the border unless the country halts its support, as well as foster resentment over alleged preferential treatment for refugees from Ukraine.

The outgoing president, Klaus Iohannis, said Sunday’s vote would in effect decide whether Romania remained “a country of freedom and openness, or collapses into toxic isolation and a dark past”.

The centre-left PSD and centre-right PNL, both members of the outgoing government, have dominated Romania’s politics for three decades, but the exit polls suggested the new legislature would be far more fragmented, making it hard to form a new coalition.

The AUR more than doubled its result of 8.5% in the previous elections. Along with the party of Young People (POT), which has backed Georgescu, and the extreme-right SOS Romania, both of which were on course to clear the 5% threshold to enter parliament, far-right parties could hold about 30% of seats in the new assembly.

If the exit polls prove accurate, a pro-west mainstream coalition led by the PSD could in principle have enough MPs to form a government, but analysts said negotiations would be difficult and could take weeks.

“The Social Democrats will take a few days and wait to be courted,” the political commentator Radu Magdin told Reuters. “A coalition with centrist parties is more likely than with the extremists. And much depends on who becomes president.”

As things stand, Georgescu should face Lasconi in a runoff on 8 December – although depending on the court’s decision, both presidential votes could be delayed until later this month, adding to the political uncertainty.

The presidential office said last week officials had detected online efforts to influence voting in the presidential ballot, with one candidate benefiting from “massive exposure due to preferential treatment” on the social media platform TikTok.

TikTok has dismissed the allegations, saying it enforced all guidelines against election misinformation.

Georgescu has called for an end to the war in Ukraine, denied the existence of Covid-19, described two second world war-era Romanian fascists as “national heroes” and claimed that in foreign affairs Romania would benefit from “Russian wisdom”.