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Matt Dunham, Associated Press
A passenger arriving to travel asks a police officer what to do as Eurostar trains are canceled at St Pancras station in London, Tuesday, June 23, 2015. Eurostar said Tuesday it has canceled all passenger trains for the rest of the day through the tunnel that links France and England, after striking ferry workers swarmed the train line setting tires alight. The move followed a day of chaos in the French port city Calais that began before dawn.

PARIS — All trains and many ferry services between Britain and France were cut off Tuesday by striking port workers, stranding hundreds of trucks and thousands of passengers on both sides of the English Channel.

Adding to the chaos, illegal migrants camped by the thousands in the port city of Calais were seen trying to stowaway on vehicles stuck in traffic jams.

Rail company Eurostar said Tuesday it has canceled all passenger trains for the rest of the day through the English Channel tunnel, after the striking ferry workers swarmed the train line setting tires alight. About 50 strikers made it onto the tracks by the freight terminal building in Calais, which forced tunnel operator Eurotunnel to close the tunnel in both directions.

Eurostar said all trains are returning to their cities of departure and none were stuck in the tunnel.

The striking workers also blocked the port in Calais, a major departure point for ferries crossing the channel, protesting feared job cuts.

The strike started before dawn, causing chaos in Calais as truckers diverted to the train line and got snarled in traffic, at which point migrants hoping to reach England swarmed the vehicles, trying to sneak on board.

Video filmed near the entrance to the Eurotunnel showed migrants racing to catch a slow-moving truck. Thousands of migrants are camped in Calais, hoping to make it to a better life in England.

Britain's foreign office updated its travel advice, warning travelers around Calais to keep car doors locked against illegal migrants trying to reach Britain.

Eurostar carries about 10 million passengers a year between Britain, France and Belgium through the Channel Tunnel.

Jill Lawless in London contributed to this report.