The European Union has warned Serbia that it may freeze negotiations on closer ties if Belgrade does not cooperate fully in capturing fugitive war crimes suspect Ratko Mladic.

EU enlargement chief Olli Rehn issued the threat Thursday as he prepared to publish a highly anticipated report next week on Serbia's progress towards EU standards.

Rehn told a committee of the European Parliament that Serbia's cooperation includes Mladic's arrest and transfer.

The U.N. War Crimes Tribunal has indicted the former top Bosnian Serb military commander for attacks on civilians during the conflict of the 1990s in Bosnia-Herzegovina.

Many Serbs regard the handover of Mladic to the tribunal as necessary to boost Serbia's hopes of eventual EU membership. But others view Mladic as a hero.

Some information for this report was provided by AFP and AP.