“We resolutely reject any accusations that we are somehow interfering in this. We are not doing this,” said Kremlin spokesman Dmitry Peskov.

However, Maia Sandu’s national security adviser, Stanislav Secrieru, said on Sunday that “massive interference by Russia” was taking place in Moldova’s electoral process, which he said had “high potential to distort the outcome”.

Sandu won the first round of the vote two weeks ago with 42.4%, well ahead of Alexandr Stoianoglo on 26%, but short of the 50% she needed to win outright. His vote is likely to increase because of the votes of candidates who failed to reach the run-off.

After voting, Sandu warned Moldovans that “thieves” wanted to buy their vote and their country and she called on them to preserve their country’s independence.

Stoianoglo, who promises to be an “apolitical president” for everyone, told reporters he had voted for “a Moldova that should develop in harmony with both the West and the East”.

But commentators and politicians have warned that a Stoianoglu victory could radically change the political landscape in the Danube and Black Sea region, not because he is some kind of “Trojan horse”, but rather because Russia has thrown its weight behind him.

By the time polls closed in Moldova at 21:00 (19:00 GMT) 54% of Moldovans had voted, with big queues reported in Moscow and Belarus as well as at polling stations in Romania, France and Italy.

Moldova’s election commission said it was aware of reports of organised and illegal transports of voters by air and land in Russia, Belarus, Azerbaijan and Turkey, and appealed to the public to report further violations.

Stanislav Secrieru said Russia had organised buses and large charter flights to bring voters to polling stations.