Despite missing Sunday's deadline, Serbian officials vowed to keep hunting the Bosnian Serb commander indicted by the UN court for genocide in the 1995 slaughter of 8,000 Muslim men and boys in the Bosnian enclave of Srebrenica, Europe's worst massacre since World War II.
If it does not surrender Mladic, Serbia faces the prospect of a suspension of its pre-membership talks with the 25-nation EU.
"It is very possible the talks will be suspended," Rasim Ljajic, the Serbian official responsible for coordinating efforts with the UN tribunal, was quoted as saying in Sunday's Blic daily.
He said he hoped any suspension would be temporary, and he added the Balkan republic's government would "continue cooperating" with the UN war crimes tribunal and eventually deliver the suspect sought by the court in The Hague, Netherlands.
"Regardless what happens, we must keep up this tempo of major operations to catch Mladic," Mr Ljajic said.
Mladic accomplices
Mr Ljajic refused to give any further information on Mladic's supposed accomplices, because that might jeopardise efforts to capture the fugitive.
"We have more information than before ... we have made progress but the European Union will only appreciate the result, not our efforts," the minister said.
The EU gave the Serbian government until April 30 to hand Mladic over or risk suspension of the next round of talks with the bloc on an accord meant to prepare the nation for eventual membership.
A previous deadline expired on March 31. At that time, Prime Minister Vojislav Kostunica pledged to deliver Mladic and promised chief UN war crimes prosecutor Carla Del Ponte that Serbian authorities were doing all they could to track him down. Del Ponte has long maintained that he is within reach of the authorities.
"No one is in a position at this moment to say when Mladic will be extradited," Mr Ljajic told Blic. "Daily operations are taking place to find him and ... we have come a long way."
Serbian Justice Minister Zoran Stojkovic declared that the arrest of Mladic, who remains a hero to ardent Serb nationalists across the Balkans, was now a "technical" matter.
In Brussels, Belgian Foreign Minister Karel De Gucht warned that Serbia's failure to meet the deadline could stall its attempts to build closer ties with the rest of Europe.
"Mladic is popular and there is support for him there but we have to put added pressure on Serbia to hand him over, or at least say where he is," De Gucht, current chairman of the Organisation for Security and Cooperation in Europe, said Sunday on VRT television.
EU Enlargement Commissioner Olli Rehn was to meet Ms Del Ponte on Wednesday to decide whether the next round of talks with Belgrade, scheduled for May 11 to discuss a trade and aid deal, would be called off.
Mr Ljajic said authorities have uncovered a support network of some
130 individuals, mostly Bosnian Serbs, who have sheltered and protected Mladic.
UN prosecutors insist Mladic is hiding in Serbia under protection of military hard-liners.
"This important intelligence should lead us to where Mladic is hiding," Mr Ljajic said.
He said five suspected Mladic aides have been in custody in Belgrade since January on charges of helping Mladic evade justice.