Making his first appearance before the International Criminal Tribunal for the former Yugoslavia since his arrest last week, Mladic told the court that he "defended my people and my country" during the 1992-95 Bosnia conflict but declined the opportunity to plead not guilty.
"I would like to read and receive these obnoxious charges against me. I want to read it with my lawyers," Mladic told a panel of three judges in The Hague.
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"I need more than a month for these monstrous words that I have never heard of," the ex-general dubbed the "Butcher of Bosnia" said of the claims.
Mladic, 69, insists he was "simply defending his country," and faces 11 charges of genocide, crimes against humanity and war crimes.
He was transferred to the International Criminal Tribunal following his arrest after 16 years on the run.
Widows and mothers of victims of the 1995 Srebrenica massacre of some 8,000 Muslim men and boys -- which forms the crux of the genocide charges -- followed the proceedings live on television in Bosnia as Mladic told the court: "I am a gravely ill man" and insisted on more time to answer the charges.
"I hope God makes him burn in hell," hissed one woman, seated among the gravestones of victims buried at the Potocari memorial centre.
"If only we could judge him here. I would like them to bring him here and we would tear him alive into little pieces," added Hanifa Djogaz, glaring at the footage.
Serbian Foreign Minister Vuk Jeremic said Friday he was confident that former Bosnian Serb army chief Ratko Mladic's trial in The Hague would help "uncover the truth" about the Balkan Wars.
The Serbian government "has worked hard in recent years on reconciliation between the Balkan states," Jeremic told a news conference during an official visit in Montevideo.
Key to achieving sustained reconciliation between nations of the former Yugoslavia, he said, was to "establish the whole truth about what happened in the awful decade of the 90s."
Jeremic said he trusted "that this process at the UN court in The Hague will help us better understand what happened, and uncover the truth," adding that he hoped others accused of war crimes against the Serbs would also face an investigation and ultimately justice.
Better known from media images as a stocky commander wearing war fatigues, Mladic appeared before judge Alphons Orie in a grey suit and gold and black tie, markedly older and thinner.
"According to the indictment you, Ratko Mladic, are charged with genocide, crimes against humanity and under rules governing the customs of war," judge Alphons Orie told the accused.
The judge set July 4 as the date for Mladic's next appearance, by when he will be required to enter pleas to the 11 charges against him.
Failing to do so, an automatic not-guilty plea will be entered on his behalf.
After spending 16 years on the run from being arrested for atrocities committed during Bosnia's 1992-95 war that killed 100,000 people, Mladic was arrested in northeast Serbia last Thursday.
The 69-year-old is accused of masterminding the Srebrenica massacre -- Europe's worst mass killing since World War II -- and the 44-month siege of the capital Sarajevo from May 1992 in which 10,000 died.
He was flown to the Netherlands on Tuesday to stand trial before the ICTY after Serbian judges denied his appeal on health grounds and found him fit to stand trial.
On the eve of the long-awaited first appearance, Mladic's lawyer Milos Saljic had said that his client was treated for cancer two years ago while evading genocide charges.
The ex-general had also suffered three strokes and two heart attacks, the lawyer said.
The trial is not expected to start for months, and should last several years.
Mladic's one-time mentor, Serbian president Slobodan Milosevic, died in The Hague four years into his own genocide trial in 2006, of a heart attack.
And his former political chief, Radovan Karadzic, has been conducting his own defence in a war crimes trial that started in October 2009.
After his rights were read to him on Friday, Mladic told the judge: "I need a bit more time to think about all the things."
He added: "I need at least two months to read those binders (provided by the prosecution), if not more."
If he pleads guilty, there will be no trial and a date will be set for a sentencing hearing. Mladic faces a maximum sentence of life in prison.
The tribunal was a hive of activity Friday as satellite TV trucks jostled for space and journalists and visitors queued since 8:00 am (0600 GMT) for the start of the hearing two hours later.
The tribunal had to rent extra space at a conference centre across the road to handle the expected overflow of visitors hoping to catch a glimpse of the ex-general in the dock.
"Mladic is a big criminal. He murdered my son, my husband, my two brothers," 69-year-old Kada Hotic, a survivor of the Srebrenica massacre, told AFP outside the tribunal.
"I hope that this court will really get the seriousness of this crime and judge in the name of justice and of victims."
She and a handful of other family members of victims addressed journalists outside the court, holding a big photo of Mladic in war fatigues and the words: "Mass murderer".
