A Eurostar passenger reportedly sparked a bomb scare at a French station after trying to board the train to London with a "military relic".
The cross-border operator said Gare du Nord station in Paris was evacuated after a "suspect package" was discovered on Saturday afternoon.
Witnesses reported scenes of confusion at the transport hub, with several saying on social media that they heard a controlled explosion.
One person wrote on Twitter: "No information on what's going on at gare du Nord!?! Massive queues, delays , explosion... Any update for your passengers?"
Eurostar replied to another person online, writing: "Somebody tried to take through a military relic so it's just being checked and check in should be open very shortly."
The high-speed service provider reassured passengers that services had not been cancelled but "interrupted until further notice".
One tweet read: "Check-in was interrupted due to the presence of a suspect package which caused the evacuation. We're sorry for the inconvenience."
Hi Lizzie, check-in was interrupted due to the presence of a suspect package which caused the evacuation. We're sorry for the inconvenience.— Eurostar (@Eurostar) August 13, 2017
Businessman Martin Adams was on his way to get the 4.13pm service to London when police cordoned off half of the station.
The 31-year-old, who had been returning from a weekend in the French capital with friends, said: "The police told us that there would be a controlled explosion and about 10 minutes later there was, nobody panicked and everybody just got about lining up for their trains.
"A lot of people missed the 4.13pm as a result but Eurostar placed people on later trains.
"My wife heard someone say in the security line that it was a tourist trying to bring a part of an old WWII bomb back through customs.
"This wasn't confirmed to us by Eurostar or security who just referred to 'security issues' when announcing delays."