A German-Syrian businessman suspected of funding al-Qaeda has been freed hours after Germany's highest court ruled his arrest warrant was invalid.
Mamoun Darkazanli: Spain accuses him of funding the 9/11 hijackers
Mamoun Darkazanli, 46, who was fighting extradition to Spain, was released from custody in Hamburg, where he had been in detention since last October.
The court ruled the new European arrest warrant violated German law.
The case was a test of the new warrant introduced last year to speed up the handover of terror suspects.
Mr Darkazanli appears in a 1999 wedding video with two of the three 11 September 2001 suicide hijackers who had lived in Hamburg.
Mr Darkazanli has not been charged in Germany, whose constitution prohibits the extradition of its own citizens.
German Justice Minister Brigitte Zypries said the ruling by the federal constitutional court was "a blow for the government in its efforts and fight against terrorism".
Spanish wanted list
After the 2001 attacks, the US froze the assets of Mr Darkazanli's Import-Export Company, saying it was a front for terrorism. He is among 41 suspects, including Osama Bin Laden, indicted by Spanish Judge Baltasar Garzon.
Correspondents say all other suspects in Germany facing extradition under similar warrants will have to be released on bail, and that the German parliament will have to pass a new law if suspects are to be held in jail on EU warrants.
After 9/11 Darkazanli's firm was targeted by the US
Mr Darkazanli's lawyers argued that handing him over under the European arrest warrant would be against the German constitution.
He has always denied any involvement in terrorism, saying he only knew the 9/11 hijackers by sight.
A spokesman for the European Commission voiced regret that Germany had failed to implement the arrest warrant and urged it to bring its national legislation into line with EU policy.
But Martin Selmayr also insisted that the arrest warrant was still valid.
"From a first reading, it's a judgment that declares null and void the German implementation law, not the European arrest warrant," he said.
In other developments, an al-Qaeda suspect being held at the US detention camp at Guantanamo Bay, Cuba, has been extradited to Spain.
Moroccan-born Lahcen Ikrassrien is accused of being a member of an al-Qaeda cell that allegedly helped plan the 11 September attacks.