Ashdown made the statement at a news conference after a two-day session of the steering board of the Peace Implementation Council (PIC) in Bosnia-Herzegovina.
The steering board once again stated clearly that the continuation of the dissatisfactory degree of cooperation of Bosnia's authorities, particularly those in Republika Srpska, with the Hague tribunal, would stop progress in the area of Euro-Atlantic integration, Ashdown said. If a small group of individuals continues to be an obstacle for Bosnian citizens to the realisation of their future in Europe, it will be necessary to take new measures, Ashdown said, refusing to reveal the nature of the measures as he said this depended on the position of NATO ministers.
The PIC session was also addressed by the chief prosecutor of the UN war crimes tribunal, Carla del Ponte, who expressed dissatisfaction with the failure of Bosnian Serb authorities to cooperate with the tribunal nine years after the signing of the Dayton peace agreement.
Ashdown, who was recently appointed the European Commission's special envoy in Bosnia-Herzegovina, said he expected the unification of Bosnia's currently divided police forces. The PIC also requested stepping up the establishment of authorities in Mostar after municipal elections in October this year.