Eurotunnel services were suspended on Saturday after more than 200 migrants broke into its French terminal in a “massive and organised” assault.
Passenger and freight services through the tunnel were halted for several hours while French police struggled to contain the invasion and remove the migrants.
Two police officers and four migrants suffered minor injuries during scuffles, local authorities of the Pas-de-Calais region said.
Around 100 of the migrants managed to walk as far as 15 kilometres into the Channel Tunnel during the mass break-in before police intervened to stop them getting any further.
“The migrants entered the south tunnel and went quite far, around 15 kilometres,” said the top official for the region, Fabienne Buccio.
A Eurotunnel spokesman described the latest incident at its Calais terminal as a “massive invasion and intrusion by a very large and co-ordinated group”.
He added: “It’s clearly an organised attack when it comes in such a large number; there are over 100 in this one group.