Some 150 migrants stranded in the French city of Calais stormed the Channel Tunnel on Saturday morning, in an attempt to make it to British territory.
The incident caused Eurotunnel train services to be delayed and even cancelled, the BBC reported.
Saturday's events came as the migrant crisis in the northern French town shows no signs of abating.
A spokesman for Eurotunnel, the company which operates the Channel Tunnel, told the BBC that "huge numbers" of migrants were seen around the area on Friday night.
For years, people from impoverished and war-torn countries in Africa and the Middle-East have been flocking to the French city in an attempt to make it into Britain -- usually on board of freight trucks.
In addition to the humanitarian crisis, authorites from both Britain and France are now having to deal with the economic costs of the migrant situation in Calais, as some companies have directed their truck drivers to no longer use the tunnel and take alternative, longer routes.
"This isn't in lay-bys off the beaten track at night, this is in broad daylight on the motorways approaching Calais and what you see, to be blunt, is marauding mobs around trailers... climbing on board, breaking open backdoors with broadly no sign of any sort of policing to prevent it," Dan Cook, operations director at Europa Worldwide, a transport and logistics business, told the BBC.
Drivers and companies caught by French authorities transporting migrants in the back of their trucks have to pay a $3,100 fine per migrant.
"It costs so much money, it's more than a salary. That's why we have to call the police," Gilles Tech, a 42-year-old truck driver, told BuzzFeed News last month.
British truck drivers complain French officials are not doing enough protect their interests.
"If we were watching television in the UK and we were seeing mass groups of people wandering around the motorway climbing on vehicles I think we would be pretty outraged and we would expect the British authorities to do something about it," Cook told the BBC.
French authorities, though, claim the migrant crisis is not their responsibility.
"Calais is not the destination. As you've heard, migrants want to get into trucks, they want to get to England. England has got to realise that it is not our responsibility," Calais Deputy Mayor Philippe Mignonet said in a statement in June.