PARIS — The campaign of French presidential candidate Emmanuel Macron said late Friday that it had been subjected to a “massive and coordinated piracy action” of emails and other internal communications.

The announcement emerged as the last official day of campaigning in France’s most contentious presidential election in decades drew to a close. Macron, an independent centrist, is facing off against the far-right populist ­Marine Le Pen. Voters are set to decide Sunday which candidate becomes France’s next president.

At the end of a high-stakes race, the news quickly stoked fears of a targeted operation meant to destabilize the electoral process, especially after reports of Russian hacking in the U.S. presidential election.

“Intervening in the last hour of the official campaign, this operation is obviously a democratic destabilization, as has already been seen in the United States during the last presidential campaign,” the Macron campaign said.

It was not immediately clear who was responsible for the hacking, which the campaign said had led to the leaking of documents via social media networks. The campaign could not be reached for further comment late Friday.