Dozens of Calais migrants try to storm Channel Tunnel
Channel Tunnel services have been disrupted after about 150 migrants tried to storm the Calais terminal.
Migrants entered restricted areas on the French side overnight, delaying and cancelling services, Eurotunnel said.
A spokesman for the firm called for "immediate action" from authorities to protect the tunnel and provide a solution to the migrant crisis.
Le Shuttle passenger services had been operating as normal, although technical problems have led to further delays.
Passengers, who are facing delays of up to two hours, are still being encouraged to check in on time.
Freight services are also delayed, Eurotunnel said, and freight lorries are queuing on the M20 for the second time this week.
Kent Police initiated phase two of Operation Stack - where freight traffic is parked on sections of the M20 - and closed roads at about 01:00 BST.
This was lifted at 14:00 and the road is now fully open.
A spokesman for Eurotunnel said there had been "huge numbers of migrants" in and around the area on Friday night.
The spokesperson said: "Up to 150 migrants stormed the tunnel, which caused disruption to services leading to delays and cancellations for customers.
"Eurotunnel wants immediate action from authorities to protect the tunnel - not enough is being done to stop the migrants."
Dan Cook, operations director at Europa Worldwide, a transport and logistics business, said "marauding mobs" of migrants were breaking into the company's vehicles.
Mr Cook said: "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.
"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."
Tim Job, from Worcester, said he saw large groups of migrants around the tunnel's entrance on Friday.
He said: "There was no police presence from the French. My wife was extremely shocked to see how laid back the authorities were."
He added that he believed French authorities had an "obligation" to protect people who use the country's roads.
Passengers currently onboard Le Shuttle services have said they have been told little about the latest "technical fault" which is causing delays.
James Johnson said: "Entered the train... for 10:06 and still waiting on the train [after] nearly an hour. Representatives on the train have not said much but will keep us informed."
And Maxine Dundas said: "Now another incident in the tunnel itself. Currently stuck in train awaiting further info.
"All we know is there is a 'technical' issue. Thankfully we are not under the sea."
Earlier this week lorry drivers in England faced days of misery as they were held in miles of queues until Operation Stack was lifted on Friday evening.
More than 3,000 lorries were parked on the M20 after the closure of the Port of Calais earlier this week crippled Channel sailings.
The chaos was sparked after MyFerryLink workers started a wildcat strike on Monday in protest at expected job cuts in the French port city.
The Port of Dover said no ferry traffic was being held in Operation Stack and there were full services to the Port of Calais and Dunkirk.