Serbian nationalist Radovan Karadzic, one of the most wanted men in Europe, has been arrested in Belgrade working as a doctor.

“Karadzic used false documents with the name Dragan Dabic,” said Rasim Ljajic, the minister in charge of cooperation with the International Criminal Tribunal for the former Yugoslavia (ICTY).

He had been posing as a doctor of alternative medicine, sporting long hair, a beard and glasses to hide his face.

A picture shown to reporters showed an unrecognisable Karadzic, markedly thin, with a long white beard and flowing hair. Serbian officials said he was walking freely around town and earned money from practising medicine.

They said they could not divulge more details because it might jeopardise efforts to arrest two other war crime suspects on the run.

Karadzic was arrested late on Monday night in Belgrade by the Serbian security services, the office of Serb president Boris Tadic said. The 63-year-old former war leader is accused of orchestrating the worst acts of brutality Europe has seen since the Nazi campaigns of the Second World War.