PARIS - The discovery of an unexploded bomb dating back to World War II has disrupted morning traffic to and from Paris' bustling Gare du Nord train station, the French national railway company said on Friday.

The disruption is affecting local metro lines, commuter rails and national and international trains, including Eurostar services.

"Due to the discovery last night of an unexploded bomb from the World War II during work carried out near Paris Gare du Nord, traffic is interrupted to and from Gare du Nord," one of the network's train lines, the H Line, said in a post on messaging platform X.

It said the move was requested by the Paris police.

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The bomb was found 2.5 km from the train station, in the middle of the train tracks, the H line said. Train traffic would be disrupted until the de-mining operation was completed.

French police did not immediately respond to a request for comment.

Gare du Nord is the world's third-busiest train station and serves trains going to and from destinations in the north of France, London, Belgium and the Netherlands, according to the Paris tourist office.

Eurostar's website showed that at least four trains scheduled to depart from Gare du Nord Friday morning had been cancelled and advised travellers to reschedule their trips.

The international train company did not immediately reply to an emailed request for comment.