Traffic along the Channel Tunnel has been disrupted overnight after migrants tried to enter restricted areas in Calais, according to reports.
"From 10.30pm (local time), around 150 migrants attempted to enter the platforms," an official for the Pas-de-Calais prefecture told the AFP news agency.
The spokesman said traffic was interrupted with long queues of lorries and cars forming, but an AFP journalist said the incident was resumed a few hours later.
However, the disruption has had a knock-on effect on traffic.
Police in Kent say they have put into action what is known as phase two of Operation Stack - where freight traffic is queued on sections of the M20 - closing parts of the road to other traffic.
Last week, lorry drivers faced days of misery as they were held in miles of queues until Operation Stack was lifted.
Kent Police tweeted: "Op Stack phase 2 implemented due to disruption at Channel Tunnel. M20 closed coast-bound 8 to 9.
"Non-freight traffic now being allowed into Channel Tunnel terminal. M20 Junctions 11 to 12 no longer closed but delays likely. Check with operator if heading to Channel Tunnel as services disrupted.