An al Qaeda suspect was freed Monday after Germany's high court blocked his extradition to Spain, ruling that a European Union-wide arrest warrant does not yet comply with German law.

The decision came as Europe moved to clamp down on terrorism after the July 7 bombings in London that killed at least 55 people, including the bombers.

Monday's ruling upheld an appeal by Mamoun Darkazanli, a German-Syrian dual national who is accused by Spain of providing the terror network with logistical and financial support.

The Federal Constitutional Court in Karlsruhe ruled that the European warrant violated the German constitution and the suspect's basic rights. Germany's constitution prohibits the extradition of its own citizens.

Darkazanli was taken into custody in October at Spain's request. His case was widely seen as a test of the new European arrest warrant, meant to allow the swift cross-border handover of suspected terrorists. It came into force in Germany in August 2004.

"From a first reading, it's a judgment that declares null and void the German implementation law, not the European arrest warrant," Martin Selmayr, a European Union spokesman, said in Brussels. Darkazanli has never been charged in Germany.

German Justice Minister Brigitte Zypries called the verdict "a blow for the government," but said a revised form of the law would be submitted within four to six weeks.

Darkazanli, 46, appears in a 1999 wedding video with Marwan Al-Shehhi and Ziad Samir Jarrah, two of the Sept. 11, 2001, suicide pilots who lived and studied in Hamburg along with the lead hijacker, Mohamed Atta.

Mamoun Darkazanli was held in Germany.