CALAIS, France (AP) — Authorities are shrinking the huge migrant camp in Calais, in northern France, pushing tent dwellers back 100 meters (110 yards) to distance them from the road leading to the port, a jumping off point to sneak to Britain.

Bulldozers moved in this week to clean the terrain after hundreds of migrants began moving deeper into the squalid camp. The move continued on Tuesday.

The prefecture has proposed giving those displaced priority in new containers opened a week ago to shelter up to 1,500 migrants. More than 4,200 are staying in Calais.

Migrants recently began blocking the port road or throwing stones to slow traffic to try to slip into trucks headed to the Calais port.

Some fear the camp will eventually be razed to rid Calais of migrants.