Kostunica said in a statement, which was forwarded to the media on Monday evening, that Ashdown's announcement about the cancellation of Republika Srpska was unacceptable.
Kostunica said in the statement that Ashdown's measures were contrary to Annex 10 of the Dayton Agreement, and that by taking these measures the High Representative had harshly violated the Agreement.
The statement also stressed that "the non-democratic and illegal measures were not helping the stabilisation of the region".
President Marovic stressed said in a statement it was necessary that the Dayton Agreement be respected "which includes full respect of both Bosnian entities and the avoiding of any unilateral move which would jeopardise (...) Bosnia's European path".
Last week Ashdown decided to replace nine police and intelligence officials and abolish the defence ministries of Republika Srpska and the Federation of Bosnia-Herzegovina (Bosnia's two entities), and ordered the establishment of police structures on the state level.
Ashdown said that the latest measures were the consequence of the Serb entity's failure to arrest any of the war crimes suspects wanted by the Hague-based tribunal, which led to NATO's repeated refusal to admit Bosnia into its Partnership for Peace programme.
Bosnian Serb Prime Minister Dragan Mikerevic tendered his resignation last Friday with the explanation that he is not ready to accept and carry out "the High Representative's threats and ultimatums on the constitutional reorganisation of Republika Srpska and Bosnia-Herzegovina," which he said represented a "harsh violation of the Constitution".
Bosnia-Herzegovina Foreign Minister Mladen Ivanic resignation last Saturday after the United State administration denied visas to PDP and Serb Democratic Party (SDS) officials. The United States decision will be in force until the Bosnian Serb entity establishes full cooperation with the International Criminal Tribunal for the former Yugoslavia (ICTY).