He appeared Thursday evening in a Belgrade court, looking frail and walking slowly as he was escorted by two guards.

Mladic's arrest removed the most important barrier to the Western-leaning Serbian government's efforts to join the European Union and to rehabilitate the country's image of a pariah state that sheltered the men responsible for the worst atrocities of the Balkan wars of the 1990s.

Mladic had two pistols when he was arrested but offered no resistance, and he appeared shrunken and pale. Serbia raised its national security level and banned all gatherings after nationalist groups pledged to pour into the streets in protest.

"We have ended a difficult period of our history and removed the stain from the face of Serbia and the members of our nation wherever they live," President Boris Tadic said in a triumphant press conference announcing the arrest. A Serbian official close to Tadic told The Associated Press that the president had personally overseen the arrest operation.

Tadic said Serbia had begun the process of extraditing the former general to the UN war crimes tribunal in The Hague, Netherlands. State TV said Mladic was undergoing medical checkups in a Belgrade detention unit at the Serbian war crimes court, before facing an investigative judge who will read him the war crimes indictment. Mladic, 69, faces life imprisonment if tried and convicted of genocide and other charges. The UN court has no death penalty.

Foremost among the horrors Mladic is charged with is the July 1995 slaughter of up to 8,000 Muslim men and boys in the Bosnian town of Srebrenica, which was supposed to be a safe zone guarded by UN Dutch peacekeepers.

Mladic seized the town and was seen handing candy to Muslim children in the town's square. He assured them everything would be fine and patted one boy on the head. Hours later, his men began days of killings, rape and torture.