The disruptions in the southern French city were a taste of what analysts warn could be far larger problems in other cases if cables are systematically attacked.

The vulnerability of fibre-optic cables, especially those underwater, and other key infrastructure has been highlighted by the sabotage last month in the Baltic Sea of natural gas pipelines from Russia.

French cable operator and internet service provider Free said its repair teams were mobilized before dawn Wednesday to deal with ``an act of vandalism on our fiber infrastructure.''

It said the attacks were simultaneous and on multiple spots of its fibre network near Marseille. Photos that Free published on Twitter showed multiple cables completely severed in their concrete housings buried in the ground. It said the cuts led to major disruptions to its network and phone services in the Marseille area.

A spokeswoman for Marseille police confirmed Friday to The Associated Press that its officers and local gendarmes are investigating multiple breakages to cables on the city's outskirts.

Cybersecurity company Zscaler said the severed cables link Marseille to Milan, Barcelona and the French city of Lyon. It said the cuts ``impacted major cables with connectivity to Asia, Europe, (the) U.S. and potentially other parts of the world.''

The damage also slowed some network traffic from Europe to India, company CEO Jay Chaudhry said.

``Since Zscaler controls the network, we were able to re-route the traffic and mitigate the issue for our global users,'' he posted.