France’s high-speed rail network was hit by a malicious conspiracy that disrupted the entire transport network, train operator SNCF said on Friday, a few hours before the opening ceremony of the Paris Olympics.

A source close to the investigators said that the attacks were coordinated acts of “sabotage”.

“This is a massive attack on a large scale to paralyse the TGV network,” SNCF said adding that many routes will have to be cancelled.

“SNCF was the victim of several simultaneous malicious acts overnight,” the national train operator said, adding that the attacks affected its Atlantic, northern and eastern lines.

“Arson attacks were started to damage our facilities,” it said, adding that traffic on the affected lines was “heavily disrupted” and the situation would last through the weekend as repairs are conducted.

A “massive attack” against France’s TGV rail transport system was an “outrageous criminal act”, Transport Minister Patrice Vergriete said on Friday.

There would be “very serious consequences” for rail traffic throughout the weekend with connections towards northern, eastern and northwestern France halved, Vergriete said, while rail operator SNCF chief executive Jean-Pierre Farandou said 800,000 passengers were affected.

Trains were being diverted to different tracks “but we will have to cancel a large number of them”, the statement said.

The southeastern line was not affected as “a malicious act was foiled”.