Simultaneously with the establishment of the NATO headquarters, the mission of the Stabilisation Force (SFOR) will be taken over by European Union forces - EUROFOR, which Gregorian said would also play an important role in the apprehension of war crimes suspects.
Gregorian dismissed the possibility of EUROFOR and NATO powers overlapping.
He also dismissed the possibility of the UN war crimes tribunal in The Hague transferring, in the course of time, all cases to the war crimes department of the Court of Bosnia-Herzegovina, which should start operating in 2005. That department will prosecute the so-called low-profile cases, while the most wanted suspects, like Radovan Karadzic and Ratko Mladic, will be tried in The Hague, he said.
Gregorian said that FBI officials were often visiting Bosnia with the aim of helping establish forces to enforce laws in Bosnia-Herzegovina, as were other US officials.
Asked to comment on recent claims by US Congress advisor Yosef Bodansky about the presence of persons linked with al-Qaida in Bosnia-Herzegovina, Gregorian said he assumed the advisor read different documents or papers than other officials.
The US diplomat said that SFOR would definitely know about the existence of possible sympathisers of a terrorist organisation in Bosnia.