Mr Subotic says he was denied legal representation

General Bogdan Subotic, held last week on suspicion of helping Mr Karadzic evade capture, was escorted to his home in Banja Luka late on Monday.

A Nato statement said the force would continue to investigate Mr Subotic's links to a war crimes support network.

Mr Subotic later said he was denied his legal rights during questioning.

Increased efforts

He accused the Nato force, S-For, of overstepping its mandate and abusing human rights.

"This was not an arrest... but a classic snatch," he told a news conference.

An S-For spokesman said they were "well within legal rights to detain individuals" accused of helping war crimes suspects.

The arrest forms part of increased efforts by Nato to hunt down Mr Karadzic and his supporters - before handing over its mission to a European Union force by the end of this year.

In January, two Bosnian Serb men suspected of aiding Mr Karadzic were held but then released.

Mr Subotic, who briefly held the position of Bosnian Serb defence minister during the 1992-1995 war, was detained last Wednesday.

Mr Karadzic is believed to be hiding in mountainous parts of Bosnia's Serb-run areas and neighbouring Montenegro.