Moldova’s crucial referendum on joining the European Union is too close to call, partial results showed Monday, as President Maia Sandu condemned an “unprecedented assault” on the country’s democracy.

Moldovans were evenly split on Monday amid final counting in a geopolitically momentous referendum on European Union accession with 50.08% in favor and 49.92% against, electoral authorities said.

Moldovan voters appear to have backed the Eastern European country changing its constitution and committing to joining the EU by the thinnest of margins. Official data put Yes on 50.31% and No on 49.69% on Monday morning, with over 99% of votes counted.