A knife-edge majority of 50.17% voted "yes" in Moldova's pivotal referendum on joining the European Union, nearly final results showed on Monday, after President Maia Sandu said Sunday's twin votes had been marred by "unprecedented" outside interference.

The first batch of preliminary results indicated the referendum on Moldova's EU future was a "no," but a last-minute spike in votes in favour from the eastern European country's diaspora evened out the score.

A referendum on Moldova joining the EU was too close to call early Monday with almost all votes counted, as pro-EU President Maia Sandu blamed an 'criminal groups working together with foreign forces' – a veiled reference to Russia – for the outcome.