Paris // France on Saturday sought to contain the spread of hacked documents from presidential front-runner Emmanuel Macron’s campaign, one day before the election.
Thousands of emails and documents were dumped online by hackers shortly before midnight in France on Friday, and were then relayed by anti-secrecy group WikiLeaks.
“The dissemination of such data, which have been fraudulently obtained and in all likelihood may have been mingled with false information, is liable to be classified as a criminal offence,” France’s electoral commission said.
“On the eve of the most important election for our institutions, the commission calls on everyone present on internet sites and social networks, primarily the media, but also all citizens, to show responsibility and not to pass on this content, so as not to distort the sincerity of the ballot,” the it said.
Mr Macron said it was a “massive and coordinated” hack aimed at “democratic destabilisation, like that seen during the last presidential campaign in the United States”.
Bound by strict election rules that ban campaigning on the day before the vote, neither he nor his allies were able to respond further as allegations were circulated on social media by his opponents in France and abroad.
Many supporters of Mr Macron’s far-right opponent Marine Le Pen ignored the warning, however, publishing screenshots of documents allegedly found in the hacked files, which the Macron team has warned could include fakes.
Senior Le Pen aide Florian Philippot suggested on Twitter that the leak might contain information the media had deliberately suppressed.
French expats in North America were already casting their ballots on Saturday, along with voters in some overseas territories in the Caribbean and Pacific.
The release of the hacked documents came on the last day of a tumultuous campaign marked by scandals, surprises and bitter exchanges between the candidates.
Mr Macron widened his support to about 62 per cent over Ms Le Pen’s 38 per cent in the final polls published on Friday before the campaigning blackout came into force.
During a bad-tempered televised debate on Wednesday, Ms Le Pen brought up unsourced allegations circulating online that Mr Macron had an offshore bank account in the Bahamas – leading her rival to sue for defamation.
There has been no claim of responsibility for the hack, although links to the files appear to have first surfaced on the US online forum 4Chan, used among others by far-right activists.
“We knew that there were these risks during the presidential campaign because it happened elsewhere. Nothing will go without a response,” French president Francois Hollande said.
US intelligence agencies believe Democratic candidate Hillary Clinton was hacked by state-backed Russian operatives ahead of the US election last November.
She has said the revelations, also spread by WikiLeaks, partly explained her shock defeat by Donald Trump.
French foreign minister Jean-Marc Ayrault suggested in February that Mr Macron was being targeted by a Russian campaign because of his support for a strong European Union which could stand up to Moscow.
Ms Le Pen is a eurosceptic who met Russian president Vladimir Putin in March.
Mr Macron’s team has previously accused the Kremlin of meddling in the campaign and being behind repeated cyberattacks on his headquarters – allegations denied in Moscow.
His campaign employs tough server protections and network encryption, but experienced hackers can always find a way in.
“In this kind of organisation the real potential fault line is the human element,” the head of computer services for Macron’s En Marche movement said recently.
Mr Macron’s team said the files were stolen weeks ago when several members of En Marche had their personal and work emails hacked in one of “an intense and repeated” series of cyberattacks.
Last month, cybersecurity research group Trend Micro said Russian hackers called Pawn Storm had targeted Mr Macron’s campaign using “phishing” techniques in which fake websites are used to trick users into revealing their passwords.
Mr Macron and Ms Le Pen – who is hoping to ride a global wave of anti-establishment anger to the Elysee Palace – have offered starkly different visions for France during a campaign that has been closely watched in Europe and around the world.
The leaks came after a frantic final day of campaigning which included the death of a Socialist lawmaker after she spoke at a Macron rally.
Corinne Erhel, 50, was the last to take the stage Friday in western France when she suddenly collapsed. She was rushed to hospital, where she was pronounced dead.
Fresh security fears also surfaced on Friday following the arrest of a suspected extremist who had allegedly pledged allegiance to ISIL.
The suspect, a 34-year-old Muslim convert, was detained near a military base outside Paris.
The arrest followed an attack on Paris’s Champs-Elysees avenue claimed by ISIL in which a policeman was shot dead three days before the first-round vote in April.
* Agence France-Presse