One of the Balkans' most-wanted war crimes suspects, Ratko Mladic, has been negotiating with the Serbian government over his possible surrender to a U.N. court in The Hague, where he would face genocide charges, Serbian officials said.

The talks with Mladic, who is charged with overseeing the deaths of thousands of Bosnian Muslim prisoners taken from the town of Srebrenica almost 10 years ago, have occurred occasionally since December, the officials said, speaking on condition of anonymity.

Although news reports here have said government forces were closing in on Mladic, Serbian officials insist his exact whereabouts are unknown. The talks, carried out at a distance through a chain of intermediaries, reportedly began at the request of Mladic, who commanded the Bosnian Serb army during the 1992-95 Bosnian war.

Prime Minister Vojislav Kostunica's government has been under heavy pressure from the United States and the European Union to resolve the cases of war crime suspects. Since last October, at least 15 wanted Serb suspects have turned themselves in, some reluctantly and out of fear of arrest.

In light of this, Serbian officials said, Mladic agreed to discuss his surrender, and has focused in talks with the government on financial security and safety for his family.

The Bush administration, which has freed up $10 million in aid to Serbia, has expressed optimism that Mladic would be sent to The Hague. Serbia is "working very seriously to find Mladic," Undersecretary of State R. Nicholas Burns said after talks last week with officials in Belgrade.

"There will be a sincere attempt to capture him or to have him voluntarily surrender and to send him to The Hague," Burns said.

The chief U.N. war crimes prosecutor, Carla del Ponte, is pressing for Mladic's arrest by July 11, the 10th anniversary of the beginning of the Srebrenica killings. "We cannot wait any longer," Del Ponte told reporters earlier this month. Also sought is Radovan Karadzic, the former leader of the breakaway Serb-populated area of Bosnia.

"I need Karadzic and Mladic in The Hague before 11 July to be able to participate in the commemoration of Srebrenica," Del Ponte said, describing those surrenders as "the only decent way to pay tribute" to the survivors.

The men -- U.N. officials say Karadzic is in Bosnia -- each face 16 counts of genocide, breaches of the laws of war and crimes against humanity. Mladic's forces killed thousands of Muslims at Srebrenica in order to "terrorize and demoralize the Bosnian Muslim and Bosnian Croat population," the indictment against him says. According to prosecutors, both Mladic and Karadzic were responsible for illegal detentions, murder, rape and ill treatment of civilians.

Videotapes circulating in Belgrade of the 1995 sequence of events in and around Srebrenica show Mladic commanding troops, chatting with civilians, promising to treat prisoners under Geneva Convention rules and brushing off U.N. officials' objections to his roundup.

He also gave interviews to Serbian television, saying, "The time has come to take revenge on the Turks," which was the label pinned by Serbs on Bosnian Muslims. At another point, a video showed him telling a crowd of women: "Don't wail. No one will harm you."

The killings in and around Srebrenica were the worst such atrocity in Europe since World War II. Bodies were buried in mass graves along a 50-mile stretch of countryside. Ever since, forensics experts have been working to identify the dead by comparing DNA samples with samples from relatives and have been able to name about 1,000 victims.

The government has moved cautiously in Mladic's case and others because of Kostunica's political concerns, officials said. The largest single political group in the country, the Radical Party, last week called for an end to "anti-Serb" hysteria over Srebrenica.

Officials said Kostunica is trying to avoid an armed assault on Mladic. And they asserted that his subtle approach has been successful.

Last October, Ljubisa Beara, a colonel in the security force during the government of former Serbian leader Slobodan Milosevic, surrendered and traveled to The Hague. The trial of Milosevic at The Hague is ongoing.

Beara had been in hiding since his 2002 indictment on charges of taking part in actions "to capture, detain, summarily execute by firing squad, bury and rebury thousands of Bosnian Moslem men and boys aged 16 to 60 from the Srebrenica area in the period from 12 to about 19 July 1995."

In January, government officials announced they were nearing "a serious breakthrough in negotiations" with major war crimes suspects. Shortly afterwards, Vladimir Lazarevic, a general during the war in the Serbian province of Kosovo, surrendered directly to Kostunica, who welcomed the move. Lazarevic got an official send-off and traveled to the Netherlands in a government-supplied plane in the company of two ministers.

His surrender set off a chain reaction. Milan Gvero, deputy commander of Bosnian Serb forces during the war, gave himself up. Then came other high-ranking officers and officials, among them Gen. Radivoj Miletic; Gen. Momcilo Peresic, who was head of the Yugoslav armed forces; Mico Stanisic, the interior minister of the self-proclaimed Serb Republic inside Bosnia; Drago Nikolic, Bosnian Serb army chief of security; and Serbian police general Sreten Lukic.

One diplomat, speaking on condition of anonymity, described Kostunica's strategy of coaxing surrenders as a means of building pressure on Mladic and eventually Karadzic. It stands in contrast to the past, when Kostunica resisted sending suspects to The Hague. "The atmosphere has definitely changed," the diplomat said.

Ratko Mladic led Bosnian Serb forces during the 1992-95 war.