France suspects members of far-left groups were behind the sabotage of the country's high-speed rail network last week just as the Olympic Games were about to begin, Interior Minister Gerald Darmanin said on Monday.

Saboteurs struck the network on Friday with pre-dawn attacks on signal substations and cables at critical points, causing travel chaos hours before the opening ceremony in Paris.

"We have identified the profiles of several people," Darmanin told France 2 TV, adding that the sabotage bore the hallmarks of far-left groups.

In recent years, France has been targeted in attacks by Islamist militants, but security services have been increasingly concerned about far-left or anarchist militants, who typically oppose the state and capitalism.

The then-head of France's domestic intelligence agency, Nicolas Lerner, told Le Monde newspaper last year French President Emmanuel Macron's divisive 2023 pension shake-up had helped lure recruits to far-left groups, which have increasingly incorporated ecological issues into their ideologies.

"In recent years, the far-left movements have been known for particularly violent clandestine actions, including arson campaigns ... ransacking and destruction of property," Lerner, who now leads the foreign spy agency DGSE, said in the interview.

In a 2023 report on terrorism trends, the European police agency Europol said left-wing and anarchist groups typically attacked "critical infrastructure, such as repeaters and antennas, government institutions and private companies" with their "most common modus operandi" being arson and improvised explosive devices.

Train services in France were back up and running by early Monday after teams worked around the clock over the weekend to fix the damage, Transport Minister Patrice Vergriete told RTL radio.

Vergriete said 800,000 people had faced travel disruptions and said the cost to the state-owned rail operator SNCF would be considerable.