Olli Rehn, EU enlargement commissioner, said the European Commission called off the talks because Serbia failed to meet Sunday's deadline to arrest Mladic. The former Bosnian Serb military leader is charged with genocide and crimes against humanity in the former Yugoslavia from 1991 to 1995.
After his telephone talk with Carla Del Ponte, chief prosecutor of The Hague tribunal, Rehn said the "commission is ready to resume negotiations as soon as Serbia reaches full cooperation," Belgrade's B92 radio said.
"Serbia must show that nobody is above law and that everybody who is indicted for serious crimes will be brought to justice," Rehn said.
Addressing a news conference, Del Ponte said she was deceived by Belgrade leaders when they told her in March they would arrest Mladic by April 30.
"The authorities in Serbia could have arrested Ratko Mladic 10 days ago," she said and added Mladic is apparently hiding in Belgrade, moving frequently from one apartment to another.
De Ponte said Belgrade authorities wanted Mladic to surrender, to avoid having to arrest him.