The Yugoslav war crimes tribunal has acquitted former Bosnian Serb leader Radovan Karadzic of one of the two genocide charges he faces at the halfway stage of his long-running trial.

Judges said on Thursday that prosecutors did not present enough evidence to support the genocide count covering mass killings, expulsions and persecution by Serb forces of Muslims and Croats from Bosnian towns early in the country's 1992-95 war.

But a second charge relating to the 1995 massacre at Srebrenica remains.

The judge said there was not enough evidence to substantiate the definition of genocide in relation to killings by Bosnian Serb forces in towns and villages in 1992.

Apart from the Srebrenica genocide charge, Karadzic also faces nine other charges of war crimes and crimes against humanity for his role in the conflict which left some 100,000 people dead and 2.2 million homeless.

"The chamber partially grants the motion and acquits the accused on count one of the indictment and denies the remainder of his request,"O-Gon Kwon, the International Criminal Tribunal for the former Yugoslavia judge, said.

Al Jazeera's Aljosa Milenkovic, speaking from Belgrade, said the move would be unlikely to provoke strong reaction in the country.

"I don't think that anybody will have a big problem about this dropping of one charge, as all the main charges still stand," he said.

Once the most powerful leader among Bosnian Serbs, 66-year-old Karadzic asked for an acquittal on all counts earlier this month, with his lawyers arguing that no genocide took place in Bosnia in 1992.

Arrested on a Belgrade bus in 2008 after years on the run, he was particularly wanted for masterminding the killings that followed the Serbs' capture of the eastern Bosnian enclave of Srebrenica in July 1995.

Close to 8,000 Muslim men and boys were murdered over the course of a few days in Europe's worst atrocity since World War II - an incident for which Karadzic has denied responsibility.

Under the tribunal's rules, the defence is allowed to seek acquittal after the prosecution has presented its case. Judges are then required to rule on the request before the defence puts forward its case, a process expected to begin on October 16.