Ratko Mladic, the former Bosnian Serb general arrested for alleged war crimes, has appeared at a closed session in a Belgrade court.
The former general, wanted for his alleged role in atrocities committed during the 1992-95 Bosnian conflict, looked frail and walked very slowly as he was escorted by four guards in the first step of the extradition process on Thursday.
He wore a navy-blue jacket and a baseball hat with grey hair sticking out the sides, and carried what appeared to be a towel in his left hand.
He could be heard on state TV saying "good day" to someone in the court. A guard could be heard telling him, "Let's go, general."
Mladic's lawyer said the judge cut short the questioning because the suspect's "poor physical state" left him unable to communicate.
Mladic faces extradition to The Hague, the Netherlands, where the UN's International Criminal Tribunal for the former Yugoslavia (ICTY), where his former political ally, Radovan Karadzic, is also in detention and 27 defendants are currently on trial.
But Mladic's lawyer said Mladic asserted that he would not answer to the authority of the UN war-crimes tribunal.
"He is aware that he is under arrest, he knows where he is and he said he does not recognise The Hague tribunal," Saljic said.
Questioning of Mladic will resume on Friday, the deputy war crimes prosecutor said.
Earlier on Thursday, the Serbian president annouced Mladic's arrest, 16 years after he was charged over atrocities he is alleged to have orchestrated during the Balkan wars.
"On behalf of the Republic of Serbia, we announce that Ratko Mladic has been arrested," Boris Tadic, the country's president, said.
"Today we closed one chapter of our difficult history that will bring us one step closer to full reconciliation in the region.
"All criminals must face justice," he said.
Tadic said the 69-year-old would be extradited to The Hague, but did not give a time frame.
Catherine Ashton, the European foreign policy chief, however, said Mladic was expected to be extradited in nine or 10 days.
Local media had first reported that a man who identified himself as Milorad Komadic had been detained and was believed to be Mladic.
According to Al Jazeera's Aljosa Milenkovic, Mladic was arrested at 05.30am (03.30 GMT) on Thursday. He was clean shaven, looked very much to himself, but much older. His right arm was apparently paralysed and he did not resist arrest.
Rasim Ljajic, the minister in charge of the search for fugitive war criminals, said Mladic "looked pale as if he had stayed indoors for a long period of time".
"Mladic had two loaded guns he did not use. He was co-operative and did not resist arrest," he said. "He spoke calmly with officers."
Belgrade's B92 radio said he was arrested in a village close to the northern Serbian town of Zrenjanin.
Bakir Izetbegovic, the Muslim member of Bosnia's three-person presidency, said the arrest was conducted in co-operation with Bosnian security agencies, but did not give further details.
The arrest was welcomed by world leaders with a spokesman for EU's Ashton describing it as "an important step forward for Serbia and for international justice".
Anders Fogh Rasmussen, the NATO secretary-general, said the arrest "finally offers a chance for justice to be done".
Mladic was indicted in 1995 over the Srebrenica massacre of 8,000 Muslim men and boys, and the 43-month siege of Sarajevo, the Bosnian capital, in which around 10,000 people died.
The UN indictment against Mladic said he was the operational mastermind behind the massacre, and also cited the establishment of camps and detention centres for Bosnian Muslims as part of a campaign of ethnic cleansing.
His arrest has been seen as a precondition of Serbia joining the European Union.
Al Jazeera's Milenkovic said "politicians from the EU have repeated time and again that Mladic is the condition for Serbia's entry" to the bloc.
Al Jazeera's Tony Birtley, who reported on the Bosnian conflict, said the capture would lead to better relations between Serbia, neighbouring Bosnia-Herzegovina, and Croatia.
"This is one of the main [factors]. The fact that they weren't giving Mladic up before was a massive stumbling block; it was holding everything back.
"Now the Serbian government can say 'let's move on and make this a better region once more'.
"It will bring closure to an ugly part of their history."
Families of victims from the Srebrenica massacre have expressed their relief over the arrest.
"For us, this is really very important," Hajra Catic, head of the Srebrenica Women Association, who lost her son and husband in the slaughter, said.
Prosecutors at The Hague have said they believed Mladic was hiding in Serbia under the protection of people who consider him a hero. He was last seen in Belgrade in 2006 but had lived openly in the country prior to the fall of Slobodan Milosevic in 2000.
But Milenkovic said it was still unclear who had helped the fugitive to hide and whether further arrests would be made.
Karadzic, the Bosnian Serb wartime political leader and Mladic's mentor, was captured in Belgrade in July 2008 and is currently on trial at The Hague.
In a message from his jail cell, Karadzic regretted the arrest of Mladic.
"President Karadzic is sorry for General Mladic's loss of freedom and he looks forward to working with him to bring out the truth about what happened in Bosnia," Karadzic's American lawyer, Peter Robinson, told The Associated Press shortly after visiting Karadzic.