People fleeing conflict and poverty in Africa, the Mideast and Asia are facing an evening deadline to move out of a camp in the French port of Calais that has become a flashpoint in Europe's migrant crisis.

Authorities, arguing that the slum-like site presents sanitary risks, warned camp residents last week that they have until 8 p.m. (1900 GMT) Tuesday to leave.

A decision is expected Tuesday in a last-ditch effort by charity groups to delay the evacuation.

Officials estimate 800 to 1,000 currently live there, but humanitarian groups contend the figure is more than 3,000.

Regional administration head Fabienne Buccio said on Europe-1 radio Tuesday that the expulsion order doesn't mean authorities will use force to evacuate the site. Interior Minister Bernard Cazeneuve insisted the evacuation would be "progressive."