Hours before the opening ceremony for the Paris Olympics, French rail company SNCF says its high-speed network has been targeted by “malicious acts” aimed at paralysing the system.

Several high-speed TGV lines have been hit to the west, north and east of Paris and queues have formed at Montparnasse station which serves destinations to the west of the capital.

Transport Minister Patrice Vergriete has strongly condemned “criminal acts” that he said would affect people’s holiday plans.

A number of trains have been cancelled and SNCF has warned that the situation could last “at least all weekend while repairs are conducted”.

Sports Minister Amélie Oudéa-Castéra described the attacks as “downright appalling”, adding that the impact on the public and Olympic athletes was currently being assessed.

More than 300,000 spectators are expected in the heart of Paris on Friday for an opening ceremony that will see thousands of Olympic athletes sailing down the River Seine.

SNCF said fires had been set alight aimed at damaging its facilities.

A source close to the investigation told AFP news agency that the attack involved acts of “sabotage”.

Although no-one has admitted targeting the high-speed network, there will inevitably be concern that it involves apparently co-ordinated acts of vandalism.

Some high-speed services have been diverted on to other lines, causing a knock-on effect to other services.