Organizers of the Paris 2024 Olympic Games are pushing ahead with the opening ceremony, despite thousands of visitors being delayed by arson attacks on the key rail lines into Paris.

The country’s rail operator said the French were under attack after the high speed system was brought crashing to a halt after saboteurs launched “malicious” and targeted arson attacks on the rail network in “an effort to destabilize” the country on the eve of the Games.

Three fires were reported near the tracks on the high-speed lines of Atlantique, Nord and Est as Paris authorities geared up for a parade along the Seine River amid tightened security for Paris 2024.

The disruption affected up 800,000 passengers and caused chaos, particularly affected Paris’s major Montparnasse station, just hours before the start of the opening ceremony where thousands of athletes are set to sail through the heart of the city in boats.

The “coordinated” series of fire attacks brought trains to a halt causing the cancellation of multiple services linking Paris to the rest of France and neighbouring countries.

It is likely to cause delays over the weekend for 800,000 passengers, with up to 250,000 affected just before the Olympics opening ceremony is due to take place on the River Seine.

Describing the consequences for the rail network as “massive and serious” with hundreds of thousands of people stuck, French Prime Minister Gabriel Attal vowed authorities will “find and punish the perpetrators of these criminal acts”. He said the vandals had the “clear objective” of strategically targeting the main routes to and from Paris ahead of the Games.