British Army bomb-disposal experts were examining a vehicle that was stopped by police near the entrance to the Channel Tunnel on Friday, authorities said.
The Kent Police force said one man had been arrested. It said the incident was not linked to the hunt for Daniel Abed Khalife, who escaped from a London prison on Wednesday while awaiting trial on terrorism charges.
“Explosives experts from the British Army have been called to the scene and a cordon has been put in place for the safety of the public. This is currently having an effect on traffic approaching the terminal,” police said.
Le Shuttle, which operates trains that carry vehicles through the tunnel between England and France, said access to its terminal was suspended and services were likely to be severely disrupted.