Former Bosnian Serb leader Radovan Karadzic has filed a motion with the U.N. war crimes tribunal for the former Yugoslavia, challenging the legitimacy of the court to prosecute him.

Karadzic faces life in prison on charges that include genocide and crimes against humanity during the Balkan wars of the 1990s.  

Prosecutors at The Hague tribunal allege he orchestrated the 43-month siege of the Bosnian capital, Sarajevo.  He also is charged with masterminding the 1995 Srebrenica massacre of as many as 8,000 Muslim men and boys.

In his motion made public on Monday, Karadzic argues that it is his "moral duty in the light of history" to challenge his prosecution.  He says he is innocent of the charges.

The trial is due to resume March 1.

Earlier this month, the U.N. tribunal ordered a court-appointed lawyer to defend Karadzic whenever he fails to appear in court.  Karadzic has been acting as his own lawyer and has boycotted several court proceedings in recent weeks.

The 64-year-old Karadzic was captured in July 2008, after nearly 13 years as one of the world's most wanted fugitives.

Some information for this report was provided by AP and Reuters.