Vandals targeted France's high-speed train network with a series of coordinated actions that brought major disruption to some of the country's busiest rail lines ahead of the Paris Olympics opening ceremony.
The state-owned railway operator said arsonists had targeted installations along the lines connecting Paris with cities such as Lille in the north, Bordeaux in west and Strasbourg in the east.
It urged all travellers to postpone their journeys. Repairs were underway but traffic would be severely disrupted until at least the end of the weekend. Trains were being sent back to their points of departure.
"Last night, the SNCF was victim of several acts of vandalism on the Atlantic, Northern and Eastern high-speed lines. Fires were deliberately set to damage our installations," the SNCF said in a statement.
The coordinated strikes on the rail network will feed into a sense of apprehension ahead of the Olympics opening ceremony in the heart of Paris later on Friday.
France is rolling out an unprecedented peacetime security operation to secure the event, with more than 45,000 police, 10,000 soldiers and 2,000 private security agents deployed. Snipers will be on rooftops and drones keeping watch from the air.
Paris 2024 said it was working closely with the SNCF to assess the situation.
There was no immediate claim of responsibility and no indication of whether the action was politically related.
Transport Minister Patrice Vergriete described the acts as criminal. The Paris police chief said he was beefing up security yet further at the capital's main stations.
Sports Minister Amelie Oudea-Castera condemned the vandalism.
"It's completely appalling," she told BFMTV. "To target the games is to target France."

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