Belgrade - Radovan Karadzic’s lawyers filed an appeal against his extradition to the UN tribunal in The Hague, the brother of the Bosnian Serb leader and war crimes suspect insisted Sunday, as public confusion about Karadzic’s expected extradition continued.

The appeal was filed on time before the legal deadline of Friday midnight, Luka Karadzic told Belgrade B92 radio station.

Earlier, Karadzic’s lawyer had refused to comment on whether the former Bosnian Serb leader had filed an appeal, saying he was under orders from his client not to speak about it.

A Belgrade court is expected to decide on the appeal Monday and immediately reject it, the radio said.

Serbia’s Ministry of Justice then needs to sign the extradition, but this is seen as a formality, paving the way for Karadzic to be turned over to The Hague by Wednesday.

Karadzic was arrested in Belgrade last Monday after 12 years on the run.

Meanwhile, Serbian investigators said that it was an anonymous telephone call to Serbia’s secret service BIA which had led to his arrest.

The investigators told Blic newspaper the caller told a BIA office that the voice of an “alternative medical practitioner” who was travelling around the country holding lectures reminded him of the one-time leader Karadzic.

The report said BIA took the anonymous call seriously and began their investigations, with BIA agents spending six weeks following the alternative medical practitioner before sweeping in to arrest him on July 21.

Radical supporters of Karadzic are planning a large-scale “All Serbs” rally in Belgrade on Tuesday.

Since his arrest, daily streets protests have erupted in Belgrade, during which several journalists were attacked and one of them seriously injured. Demonstrators also clashed with police and smashed offices and bars.

On Saturday, thousands of Bosnian Serbs also attended peaceful protests and prayers in towns across the Bosnian Serb entity, the Srpska Republic, in support of Karadzic.

Serb President Boris Tadic has received death threats, many in the forms of e-mails to his office, and security measures for Tadic, several ministers and prosecutors have been stepped up, officials said Sunday.

Authorities have also initiated an investigation against a high- ranking member of the opposition, ultra-nationalist Radical Party, officials said.

The oppostion official, Vjerica Radeta, on Friday had called Tadic “a traitor” and warned he could end up like late Serbian prime minister Zoran Djindjic. She had also accused Tadic of sending “provocateurs” to beat up journalists who covered street protests in Belgrade.

Djindjic, then leader of Tadic’s Democratic Party, was killed in 2003 by special police forces of Slobodan Milosevic’s special police forces. His government had extradited the late Serbian autocrat to the UN war crimes tribunal in The Hague in 2001, where he died in 2006.

Tadic, who succeeded Djindjic as the head of the Democratic Party, earlier this month formed a pro-European government with Milosevic’s Socialists.

Blic’s account of Karadzic’s arrest followed reports on how the long-running fugitive was finally tracked down. Early accounts had said that police got onto Karadzic’s trail while seeking his military chief, Ratko Mladic.

Two days after Karadzic’s capture, Interior Minister Ivica Dacic was quoted as claiming that the BIA had protected Karadzic, 63, during his years in hiding and in the end it was the BIA which then “handed him over.”

The Hague-based International Criminal Tribunal for the former Yugoslavia (ICTY) has indicted Karadzic for war crimes, genocide, crimes against humanity and severe breaches of the Geneva Conventions during the 1992-95 war in Bosnia-Herzegovina.

Karadzic has said he will defend himself at the tribunal, like his late mentor Milosevic. (dpa)