Nato have targeted Ljiljana Karadzic's houses

The pre-dawn operation on a house owned by his wife came days after dozens of troops raided other properties.

Mr Karadzic and his military leader, Ratko Mladic, are the most wanted of the Bosnian Serb alleged war criminals to remain at large.

But repeated attempts to track them have failed, and Tuesday's raid also appeared unsuccessful.

Nato-led troops moved in at 0100 local time (2400GMT) to the house in a village near the town of Pale.

S-For spokesman Dave Sullivan told Reuters news agency the raid followed intelligence gathered from the operations in Pale itself at the weekend.

Karadzic led Bosnian Serbs in the bloody conflict

One person found in the house was questioned but not detained, he said.

"Material of potential intelligence value was removed from the house," he added.

The weekend operations involved some 200 troops from the UK, Italy, Germany and Bulgaria.

Another house belonging to Mr Karadzic's wife was searched, along with church and hospital buildings. Nato said then it had information that Mr Karadzic had been seeking medical help.

Pale, 16 kilometres (10 miles) outside the Bosnian capital, Sarajevo, was a wartime stronghold of Mr Karadzic.

He faces charges of genocide over the siege of Sarajevo and the Srebrenica massacre, as well as other war crimes and crimes against humanity.

The Karadzics' daughter, Sonja, told journalists the family had been "practically imprisoned" since Saturday.

"I am outraged with S-For because they are molesting my family and children," she said.