It is based on three strands. strand A organises cross-border cooperation between regional and local authorities in border regions, at both internal and external borders of the European Union, on the basis of joint cross-border development strategies which Member States' local and regional authorities are responsible for implementing. strand B governs transnational cooperation between national, regional and local authorities in various Member States or applicant countries regarding regional development, transport networks and the environment. Member States, i.e. national authorities, are responsible for implementing this strand.