French CRS riot policemen react to a protest by migrants against the partial dismantlement of the camp for migrants called the "jungle", in Calais, northern France, February 29, 2016. [Photo/Agencies]

Many attempt to climb illegally onto trains using the Channel Tunnel or into lorries heading to Britain where they hope to settle. Their presence has led to tension with some of the local population and to a permanent police deployment.

Earlier on Monday at another European migrant crisis flashpoint, Macedonian police also fired tear gas to disperse hundreds who stormed the border from Greece. The migrants had torn down a gate as frustrations boiled over at restrictions imposed on people moving through the Balkans.