The tunnel that runs underneath the English Channel was closed Tuesday afternoon, severing the connection between the European continent and the British Isles, leaving travelers stranded.

All forms of traffic between Britain and France were suspended, starting at 3 p.m. local time, because protesters broke into the tunnel entry site on the French side and set tires on fire, a source told CNN.

The current protest is the result of fears that workers might lose their jobs next month, according to Sky News, due to restructuring.

On Tuesday, rail company Eurostar said it would cancel all passenger trains for the rest of the day, not solely because of the fire, but also because about 50 strikers made it onto the tracks in Calais, France, forcing tunnel operator Eurotunnel to close the tunnel in both directions.

Adding to the chaos, illegal immigrants camped in Calais were seen trying to stowaway on vehicles stuck in traffic jams. A video even shows immigrants racing to catch a slow-moving truck.

This revelation prompted Britain's foreign office to warn travelers around Calais to keep their doors locked to prevent illegal migrants from reaching Britain.

A Eurotunnel spokesman stated that traffic would return to normal shortly.