Eurostar trains parked at platforms as traffic has been stopped at the Gare du Nord station in Paris on Friday.

Paris CNN  — 

Trains to and from Paris were heavily disrupted following the discovery of an unexploded World War II bomb early on Friday near the world’s third-busiest train station.

Almost 500 trains were canceled and the disruption affected around 600,000 people at the Gare du Nord, the transport minister said.

The bomb, described by a spokesperson for France’s national rail company SNCF as “really huge,” was discovered by construction workers on a site to replace a railway bridge. It was found 2.5km outside of Paris, along railway tracks in the nearby town of Saint Denis.

“The bomb could be a serious threat to people’s lives,” the spokesperson warned. The bomb weighs 500kg, including 200kg of explosives.

The finding led to the severe disruption of both domestic and international travel at Paris’s bustling Gare du Nord station, which an estimated 220 million visitors pass through every year. Services to London and Brussels were hit, Eurostar said.

French transport minister Philippe Tabarot said that train services will gradually resume and roads will reopen later Friday from 6pm local time although it wasn’t immediately clear how the bomb was made safe or disposed of.

“We are delighted and relieved that all these worries are ended,” Tabarot said.

Following the bomb’s discovery, a security perimeter was immediately established, leading to the disruption of the intercity and suburban lines from Gare du Nord, police told CNN.

Later Friday, the security perimeter was extended to 500 meters, according to the Saint Denis town hall. All buildings in the vicinity with windows facing towards the bomb were also evacuated.

A view of a departures screen at St Pancras International station in London on Friday.
Passengers wait inside the departure hall at Gare du Nord on Friday.

Several hundred passengers were inside the Gare du Nord looking for information on Friday morning, CNN saw. The atmosphere was calm, with dozens of train staff and security personnel helping passengers.

One woman told CNN affiliate BFMTV from outside the station, “We were supposed to leave for a weekend in London this morning. The worry is that we will lose €800 worth of hotel rooms if we don’t make the reservation, so that’s a bit of a problem.”

Another woman said, “There is no information being given on the app, only the Eurostar site that says that we can be reimbursed. Aside from that, no further information.”