BELGRADE, Serbia (AP) - Ultranationalists are planning a huge anti-government rally in Serbia's capital Tuesday evening, and Radovan Karadzic's lawyer predicted the government will try to whisk the arrested war crimes suspect off to the U.N. tribunal before the protest.

Belgrade was rife with fears there could be clashes in the streets Tuesday evening as the ultranationalists plan to prevent the extradition of the ex-Bosnian Serb leader to the U.N. tribunal at The Hague, Netherlands.

The rally organizers - the right-wing Serbian Radical Party - are busing Karadzic's supporters in from all over Serbia and Bosnia where Karadzic is revered as a wartime hero who helped create the Bosnian Serb mini-state after the bloody 1992-95 war.

The last time the nationalists organized a rally against Western countries that recognized Kosovo's independence in February, the U.S. Embassy was partly burned and protesters went on a looting spree, smashing shops and McDonald's restaurants in Belgrade.

"The protest is against the treacherous and dictatorial regime" of Serbia's pro-Western President Boris Tadic which arrested Karadzic last week after nearly 13 years on the run, Radical Party leader Aleksandar Vucic said.

Ivana Ramic, the spokeswoman for the court in Belgrade dealing with Karadzic's case, told The Associated Press on Monday that his appeal against the extradition to the U.N. court had not arrived by the time the court had closed for the day.

In case the appeal doesn't arrive within a "reasonable timeframe," Ramic said, the court's investigative judge will rule on Karadzic's extradition.

Karadzic's lawyer Svetozar Vujacic said he mailed the appeal at the last possible moment late Friday, trying to delay Karadzic's extradition to the U.N. tribunal until after the rally.

"Karadzic is a Bosnian Serb citizen, so it would be logical that the appeal was mailed from Bosnia," Vujacic said. "I wouldn't rule out that my appeal grows a beard and mustache before it gets here."

Karadzic faces 11 charges at the U.N. tribunal, including genocide and conspiracy to commit genocide. He is accused of masterminding the 1995 slaughter of 8,000 Muslim men and boys in Srebrenica and the more than three-year siege of Sarajevo, which left 10,000 people dead.

Officials say the war crimes suspect was captured July 21 in Belgrade, where he lived under an assumed identity of a health guru masked in a long white beard and hair. His lawyer claims that Karadzic was kidnapped in a Belgrade public bus July 18, and illegally held for three days by unknown captors.

Serbia's state television showed footage Monday of a bearded Karadzic with a white hat purportedly made a month ago in a village close to Belgrade during his visit to an alternative fertility clinic. The informal gathering was called "talking about sex," the report said.

Interior Minister Ivica Dacic said a search of the Belgrade apartment where Karadzic lived yielded copies of wartime Bosnian documents, including minutes of meetings of the Bosnian Serb army chief of staff during the 1992-95 Bosnian war.

The onslaught in Srebrenica - considered the worst carnage in Europe since World War II - came after orders from such a meeting. Dacic said the documents have been handed over to the Serbian war crimes court.

Prosecutors were studying Karadzic's U.N. war crimes indictment at The Hague on Monday to see if they need to update it before his trial begins. Prosecutors say they are considering recent jurisprudence and possible new evidence.

Karadzic's 11-count indictment was last amended on May 31, 2000.

Vujacic said that he wants to prevent his client's extradition before the ultranationalist rally.

"They (the authorities) are using all illegal means to try send him to The Hague before the rally," Vujacic said. "Karadzic and I want to make sure it does not happen."

Once Serb judges decide on the appeal - which they are likely to reject - the case will be handed over to Serbia's justice minister, who issues final extradition orders.

Serbia's new, pro-Western government hopes that Karadzic's arrest will strengthen the country's bid for EU membership. Serbia had been accused of not searching for war crimes fugitives sought by the U.N. tribunal.