BANJA LUKA, Bosnia-Herzegovina (AP) – The prime minister of the Bosnian Serb-run half of the country resigned Friday, a day after the U.S. government and Bosnia’s top international administrator sanctioned Bosnian Serbs for failing to arrest and hand over war crimes suspects to the U.N. tribunal.

Dragan Mikerevic said he was “not prepared to accept the threats and ultimatums.” Bosnia’s top international administrator, Paddy Ashdown, and U.S. Ambassador to Bosnia Douglas McElhaney on Thursday announced sanctions against Bosnian Serb officials.

“From the standpoint of my personal political views … and especially moral standards and the sense of responsibility I have for the destiny of the Serb Republic and Serb people, I decided to resign,” Mikerevic said, adding that he hoped the Serbs would “understand and appreciate the good intentions in my decision.”

The U.S. sanctions included a travel ban for the leadership of Mikerevic’s party and one founded by Bosnian Serb wartime leader Radovan Karadzic.

The Dayton peace agreement that ended the 1992-95 Bosnian war says all authorities must cooperate with the U.N. war crimes tribunal, based in The Hague, Netherlands.

The Bosnian Serbs have not arrested any of the war crimes suspects believed to be hiding in their territory.

Bosnia’s two most wanted war crimes fugitive suspects are Karadzic and his top general, Ratko Mladic.

Both were indicted for genocide and crimes against humanity.