With France's presidential election just a day away, the frontrunner, Emmanuel Macron, said his campaign has been hit by a "massive" cyber attack.
Macron is the centrist candidate facing far-right Marine Le Pen in the landmark election. His campaign said a mix of authentic and fake documents were put on social media to sow "doubt and misinformation" and undermine Macron ahead of the election, according to reports.
As much as nine gigabytes of data including emails were posted on a website that allows anonymous document sharing. It was not immediately clear who was responsible for posting the data, but suspicion has fallen to Russia after it allegedly interfered in the US election.
Macron's former economy minister previously complained about attempts to hack the campaign's emails, blaming Russian interests in part for the attacks. The team said an attempted cyber attack was made on April 26, but no information was stolen.
Russia has denied it was behind any such attack, according to Reuters.
Macron's party, En March!, said in a statement:
The En Marche! Movement has been the victim of a massive and coordinated hack this evening which has given rise to the diffusion on social media of various internal information.
A ban on campaigning took effect at midnight yesterday ahead of voters heading to the polls Sunday.
The latest survey shows Macron winning with about 62 per cent of the vote.