A new European border and coast guard force has been officially launched at a checkpoint on the European Union's external border with Turkey in Bulgaria.

The new task force, launched at the Kapitan Andreevo crossing on Thursday, was built from the border management agency Frontex because national coast guards were overwhelmed by the refugee emergency.

Dimitris Avramopoulos, the EU commissioner for migration, home affairs and citizenship, said: "From now onwards, the external EU border of one member state is the external border of all member states — both legally and operationally."

The service will have more than double Frontex's staff and new powers. EU countries will establish a pool of 1,500 guards and technical equipment to rapidly deploy to countries battling heavy migration flows.