France vowed on Tuesday to stem the flow of illegal immigrants who sneak onto trucks and boats in the northern of port of Calais to cross over the Channel to Britain.
"We are studying technical solutions to make the zone watertight," said the newly-appointed Immigration Minister Eric Besson during a trip to the town, which is home to hundreds of immigrants trying to get to England.
The issue has long been a bone of contention, with London irked by France's failure to stop unauthorised transit through Calais to Britain by people from Afghanistan, Pakistan, Iraq, sub-Saharan Africa and elsewhere.
Besson said after visiting a makeshift migrant camp nicknamed "The Jungle" that early next month he would meet his British counterpart, and promised to announce "concrete solutions" to the problem by May 1.
Calais became a destination for migrants in the late 1990s with the opening of the Sangatte refugee camp, right next to the entrance to the Channel Tunnel linking France and Britain.
The camp was finally closed in 2002 but migrants still come to Calais in their attempts to get to Britain. Every night, migrants attempt to hide in trucks and trains using the tunnel or ferries to cross the Channel.