London (PA Media/dpa)
Eurostar has suspended services between London and Paris for the rest of Friday after the discovery of an unexploded World War II bomb near tracks in the French capital.
Thousands of passengers face travel disruption as the cross-Channel operator was scheduled to run 32 trains in either direction throughout the day.
A large crowd of people who were booked on affected services gathered outside the check-in area at London St Pancras station.
Fridays are one of the busiest days of the week for Eurostar, as many leisure travellers embark on international weekend breaks. A spokesperson for the operator said the bomb was discovered during work near the Gare du Nord station, north of central Paris.
Eurostar said services between Paris and London and between Paris and Brussels would resume on Saturday.
"Eurostar will run two additional trains: a train leaving London for Paris in the morning, and a train leaving Paris for London in the afternoon," the cross-Channel operator said.
Gare du Nord is also used for mainline services in France, and is considered the world's busiest railway station outside of Japan.
France's national train operator SNCF said earlier in a statement that services at Gare du Nord would be suspended until mid-morning at the request of the police.
It added: "We invite travellers to postpone their trip."
Eurostar is giving passengers whose trains have been cancelled the option of either requesting a refund or voucher for the value of their booking, or to re-book for travel on an alternative service.
Eurostar service between London and Brussels is unaffected.