An unexploded WWII bomb discovered near tracks leading to France's busiest train station has severely disrupted rail service as police work to disable the device.

All domestic and international trains at Gare du Nord, Europe's busiest train station, came to a halt Friday after an unexploded World War II shell was discovered, officials said.

Eurostar has suspended all of its services between London and Paris on Friday after the discovery of an unexploded Second World War bomb near tracks in the French capital.Thousands of passengers have had their travel disrupted with videos and images showing people stranded in Paris’ Gare du Nord and London St Pancras.