Police in the southern Spanish city of Granada have arrested a leading Arabic TV journalist on suspicion of links to Islamic militants.
Alouni became well-known for his work in Afghanistan
Tayseer Alouni, Syrian by birth but now holding a Spanish passport, was arrested at his home by police with a warrant, his wife said.
Judge Baltasar Garzon ordered Mr Alouni's detention on suspicion of links with al-Qaeda as part of an investigation into Islamic militant operations in Spain.
Mr Alouni, a correspondent for the Qatar-based television channel al-Jazeera, became well-known for his work in Afghanistan during the US-led war there.
He was one of the few reporters allowed to work under the Taleban regime and interviewed Osama Bin Laden in October 2001.
Al-Jazeera has condemned Mr Alouni's arrest and says it has contacted human rights organisations for support.
"There are other journalists who have relations with al-Qaeda suspects and there are other networks who air tapes and statements from al-Qaeda," the channel's editor-in-chief Ibrahim Hilal told the Associated Press.
"Why is al-Jazeera's correspondent the one arrested then?"
Police sources said Mr Alouni had been taken to Madrid after his arrest at noon on Friday.
The sources said Mr Alouni was suspected of giving support to Edin Barakat Yarkas, also known as Abu Dahdah, who was arrested in Spain in November 2001 on suspicion of being the leader of an Islamist fundamentalist cell in the country.
Mr Alouni is expected to appear in court on Monday.
His wife, Fatima, told al-Jazeera that her husband had been picked up by plainclothes officers.
"Police in civilian clothes came to our door with a warrant
to search the house and to arrest Tayseer..." she said.
A report on al-Jazeera's website said they had been informed by Spanish intelligence sources that Mr Alouni is being held under anti-terrorist laws and so can be held for three days while being questioned without access to a lawyer.
A number of suspected al-Qaeda members have been arrested in Spain since the 11 September attacks in New York and Washington.
Some have been accused of links to the attack and remain in custody but others have been released because of lack of evidence.