A Swiss-held prisoner who stands accused of links to terrorist activities has appealed against his extradition to Spain.
The move comes one day after Switzerland opened its own investigation into Mohamed Achraf, who is suspected of masterminding an alleged plot to blow up the National Court in Madrid.
Officials confirmed on Sunday that Achraf was being detained by the Swiss Federal Prosecutor's Office.
But they declined to say whether he had been moved from a detention centre for illegal immigrants at Zurich airport.
Achraf told the Swiss authorities on Friday that he would fight any attempt to extradite him to Spain.
The Spanish government said a formal extradition request had been issued, but a spokesman for the Swiss justice ministry said the suspect had the right to lodge an appeal and that the legal wrangling coud drag on for "several months".
Also on Friday, the Federal Refugee Office confirmed that Achraf had lodged an asylum claim in Switzerland in April 2003. Six months later, his application was turned down.
"After that, he disappeared," said spokesman Dominique Boillat.
Although not hunted by police, the 31-year-old was arrested on August 28.
He was awaiting deportation when officials learned he was allegedly linked to the Spanish plot.
Achraf was transferred to solitary confinement this week after his alleged terror ties emerged - thanks to information from Spanish police and fingerprints taken by Swiss authorities when he sought asylum in 2003.
Spain alleges that Achraf masterminded a foiled plan to detonate a lorry laden with 500kg of explosives outside the country's National Court, a hub for investigations of terror cases.
Baltasar Garzon, the Spanish judge leading the investigation, has filed terrorism charges against 17 people in Spain for their role in the alleged plot.
Garzon said the suspects were thought to have been part of a cell set up by Achraf and others, while he was serving time in a Spanish prison between 1999 and 2002. Achraf was not among those charged on Saturday.
Switzerland's Federal Prosecutor's Office announced on Thursday that it had launched its own investigation into Achraf.
Spokesman Hansjürg Mark Wiedmer said Swiss officials were working closely with the Spanish authorities.
He added that there had been meetings between representatives of the prosecutor's office and Garzon.
Phone and mail
It emerged on Thursday that Achraf had been able to make telephone calls and send uncensored mail from his Swiss cell because prison authorities were unaware he was a terror suspect.
Victor Gähwiler, head of canton Zurich's prison service, said he was surprised to learn that Achraf stood accused of masterminding an alleged plot to kill judges in Spain investigating Islamic militants.
Spanish police are thought to have intercepted calls made by Achraf and found mailed instructions from him.
"I got very angry when I learned from the media that we apparently had a highly dangerous terrorist with us," said Gähwiler.
He added that the lack of information from Swiss federal prosecutors was "surprising".
Spanish police arrested seven other suspects on Monday in Madrid and southern Spain, and one more on Tuesday in the city of Pamplona.
Most are Algerian, and some are suspected of contacts with militants elsewhere in Europe, the United States and Australia.
The alleged terror cell is also believed to have links to the Netherlands. One suspect taken in by the Dutch authorities is reported to have been forging passports for a terror network.
Garzon has been leading Spanish terror investigations launched in the wake of the September 11 attacks in the US.
This week's arrests come seven months after the March 11 train bombings in Madrid, which killed 191 people. They have been blamed on Muslim militants linked to al-Qaeda.
swissinfo with agencies
April 6, 2003: Achraf lodges asylum claim with Swiss authorities.
October 22, 2003: Federal Refugee Office rejects his application; Achraf goes underground.
August 28, 2004: Achraf is arrested by Swiss police and transferred to a detention centre at Zurich Airport.
October 20, 2004: Spanish police name Achraf as suspect in alleged plot to bomb National Court in Madrid.
October 21, 2004: Swiss Federal Prosecutor opens investigation into Achraf's alleged links to "terrorist activities".
October 22, 2004: Achraf appeals against extradition to Spain.
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