All Eurostar trains between London and Paris will remain suspended for the rest of the day following the discovery of an unexploded Second World War bomb near the tracks.
French police have since closed Paris Gare du Nord - one of the French capital's busiest train stations.
The disruption has caused significant travel chaos for passengers attempting to travel between the two capital cities.
French police have shut down all traffic to and from the station following the find "in the middle of the tracks" in the Saint Denis area, according to French national railway company SNCF.
Paris Gare du Nord, one of the French capital's busiest train stations, has been closed after the discovery of a World War Two bomb on nearby tracks
Getty/ PA
The bomb's discovery prompted immediate action from authorities, with Paris police working to disable the device.
The unexploded ordnance has halted operations at the major transport hub, which serves as a terminal for Eurostar, high-speed and local train services.
Eurostar's website shows at least 10 trains scheduled to depart from Gare du Nord this morning have been cancelled.
The disruption extends to RER, regional and TGV trains, as well as international Eurostar services.
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All these services are suspended until at least 10am, according to SNCF.
A bomb squad has been working at the scene since approximately 6am.
Passengers are advised to check with operators before travelling to the station.
Eurostar said: "Due to an object on the tracks near Paris Gare du Nord, we are expecting disruption to our services this morning.
"Please change your journey for a different date of travel."
Pictures from Gare du Nord station show large queues of people forming as the travel disruption continues.
Passengers have been left waiting in long lines as they seek information and alternative travel options.
