France's high-speed rail networks have been disrupted by what authorities labelled "coordinated" attacks, including arson, affecting some 800,000 travellers. 

State-owned railway company SNCF said travel on its railway lines would be disrupted until at least Monday, and Eurostar also confirmed its rail services between London and Paris had been disrupted by the acts of vandalism, resulting in several cancellations and longer journey times.

"I don't have concerns, we have full confidence in the French authorities. All the measures are being taken. The French authorities are assisted by 180 other intelligence services around the world," Bach told the BBC.

Paris police chief Laurent Nunez said Friday that police are stepping up security and focusing manpower on the capital’s train stations. The French Minister of Sports and the Olympic and Paralympic Games, Amélie Oudéa-Castera, said the organisation will "assess the impacts on travellers, athletes, and ensure the proper transport of all delegations to the competition sites”.

Christophe Dubi, the Olympic Games executive director, told the BBC he had seen a "quick reaction" from organisers.

"The organisers, including authorities and SNCF, have to prepare for different scenarios. What I see here is a quick reaction and that gives me a lot of confidence. I have to feel for all those impacted by these delays, but I have confidence that organisers are really well prepared for any situation and this is definitely one,” he said.

The Olympic Games in Paris kick-off with the opening ceremony at the Seine at 19:30 CEST (18:30 GMT).