Moldova's referendum on joining the European Union held a narrow 50.17% majority, according to nearly final results Monday, amid claims of "unprecedented" foreign interference by President Maia Sandu.

The tight finish – with fewer than 1.5% of the ballots still to be counted – is far from a resounding endorsement of the pro-EU path that Sandu has pursued over four years at the helm of the small ex-Soviet republic tugged between Russia and the West.

A presidential election, which took place simultaneously, handed Sandu 42% of the vote while her main rival, former Prosecutor General Alexandr Stoianoglo won 26%, setting up a tightly fought run-off between the two on Nov. 3.

The votes, which took place after a slew of allegations of election meddling, were seen as a test of the southeast European nation's commitment to join the European Union and escape Moscow's orbit for good.

The tight referendum result puts Sandu in a weaker position going into the second round since she has championed EU integration.

Moldova began the long process of formal accession talks in June and under Sandu has aimed to join by 2030. Ties with Moscow have deteriorated as Sandu condemned the Kremlin's invasion of Ukraine and diversified energy supply away from Russia.

Stoianoglo has said that, if he comes to power, he would develop a "balanced" foreign policy involving ties with the EU, Russia, United States and China. He boycotted Sunday's referendum, calling it a ruse to boost Sandu's haul at the election.

'Clear evidence'

In the early hours of Monday, Sandu addressed Moldovan citizens, saying there was "clear evidence" that criminal groups working together with "foreign forces hostile to our national interests" had sought to buy off 300,000 votes.

She said this amounted to "fraud of unprecedented scale."

"Criminal groups ... have attacked our country with tens of millions of euros, lies and propaganda, using the most disgraceful means to keep our citizens and our nation trapped in uncertainty and instability," she said.

While still waiting for the final results, she said, Moldova would "respond with firm decisions," without elaborating.

Russia, which accuses Sandu's government of "Russophobia," denied interfering.

Ahead of the vote, authorities took down online resources they said hosted disinformation, and announced they had uncovered a program in Russia to train Moldovans to stage mass unrest.

As the early results came in late Sunday, some 57% of Moldovans initially appeared to have voted "no" in the referendum. As more ballots were counted, the "yes" vote gradually rose, overtaking "no" early Monday morning.

Political analyst Valeriu Pasha said the "yes" vote had edged ahead only because of unusually high voter turnout among the Moldovan diaspora living abroad, who largely support EU integration.

"With such elections, in which dozens of (percentage points) can be bought, it will be very difficult for us going forward. But we must learn lessons and learn to fight this phenomenon," he said.