Seven out of 10 French high speed trains will run Saturday on three key routes, a day after saboteurs paralysed much of the train network as the Olympic Games started in Paris.

No immediate claim of responsibility was made for the coordinated overnight arson attacks on cabling boxes at junctions strategically picked out north, southwest and east of the French capital where the Olympics opening ceremony was staged on Friday night.

Rail workers thwarted an attempt to destroy safety equipment on a fourth line in what the SNCF rail company called a “massive attack”.

“On the North, Brittany and South-West high-speed lines, seven out of 10 trains on average will run with delays of one to two hours,” SNCF said in a statement.

It said SNCF “agents worked all night under difficult conditions in the rain to allow to improve traffic on high-speed lines affected by the acts of sabotage.

“At this stage, traffic will remain disrupted on Sunday on the North axis and should improve on the Atlantic axis for weekend returns,” it said.

“Customers will be contacted by text message and email to confirm the running of their trains.”

SNCF estimated that about 250,000 passengers were affected on Friday. Junior transport minister Patrice Vergriete said 800,000 could face the fallout over the three days.

The coordinated attacks were staged at 4:00 am (0200 GMT) early Friday.