Traffic was suspended in both directions in the Channel Tunnel between Britain and France on Saturday after a lorry fire, authorities said, hoping partial service could restart later in the evening.
A screen displays cancelled train information at St Pancras International station in London on January 17, 2015, after all Eurostar trains were cancelled for the day due to a lorry fire in the tunnel
"Due to an incident in the tunnel, all departures are currently suspended in both directions," tunnel operator Eurotunnel said.
It said it might be able to resume rail service for vehicles and freight on Saturday evening in one of the two tunnels.
"A tunnel inspection is currently under way and we anticipate that we will be resuming services this evening," the firm said.
Eurostar meanwhile cancelled all its passenger trains until Sunday, when it said it expected to resume a "near-normal service".
"We are sorry but we are unable to run any further trains today because Eurotunnel has been closed due to smoke detected in the north tunnel," the firm said on its website.
Passengers affected by the cancellations were advised to postpone their journeys and not to come to the station.
All Eurostar trains already en route were forced to turn back to their stations of origin, while 42 people were evacuated from the truck shuttle using the service tunnel.
Police in southern England said the fire was "at the French end of the tunnel and is being dealt with by the French authorities."
"There are no reported injuries," police added.
"There was a lot of smoke," said Denis Gaudin, a local official from the northern city of Calais.
"We don't know the extent of the damage," he said, adding that it "was not a major fire".
Eurostar, which offers passenger rail services between London, Brussels and Paris, said its trains would resume on Sunday morning, with some delays.
"The hypothesis is that we will only have one of the two tunnels tomorrow, so we will have delays all day," the company's chief executive Nicolas Petrovic told AFP, adding that "several thousand" customers had their travel plans disrupted by the incident.
- Travel chaos -
The fire sparked travel chaos in both Britain and France with long queues for refunds reported at London's St. Pancras station.
"The Eurostar people told us to watch the Internet for updates. We're going to find a hotel close to the station so we're covered for any eventuality," said one stranded passenger in Lille, northern France.
John Taehan, a tennis coach with eight young players, had given up and was seeking an alternative route.
"They told us to take a train to Calais and then the ferry and that's what we're going to do," he said, flinging his rackets over his shoulder.
A third passenger, 52-year-old Marie from Lille, complained about a lack of information.
"Last summer, during the SNCF (French rail company) train strikes, we got text messages when trains were cancelled," she said.
"Here, we got nothing. We just got here and we were told that the train was cancelled."
- 'Full service tomorrow' -
In November 2012, a fire on a freight train halted traffic in the tunnel for two hours.
Four years earlier, a lorry fire caused major damage in the tunnel, affecting 650 metres of the structure and gumming up traffic for 30 hours.
Some 400 trains and 1.5 million lorries pass through the tunnel every day.
A Eurotunnel spokesman said inspectors were examining the site for damage, adding: "It doesn't look like anything significant at this stage. We hope we will be running a full service tomorrow."