France's top security official said investigators have dismantled 25 migrant smuggling networks in the country's north in the past year.

Interior Minister Bernard Cazeneuve said about 700 people were involved in the networks in the Calais region, temporary home to about 4,000 migrants camped in squalid conditions on the edge of the Channel in hopes of slipping across to a better life in England.

Speaking Thursday to Europe 1 radio, Cazeneuve also defended his ban on protests in Calais, which he said was imposed in response to a demonstration in support of migrants that ended with a group of people breaking into the port and boarding a ship. He said the unrest showed the risks were too great of confrontations involving both pro-migrant activists, and extremists on the right.