Germany's Federal Constitutional Court on Friday upheld a ban on the radical Islamist group "Kalifatstaat" (Caliphate State), whose leader is fighting extradition to Turkey. The court ruled that the militant stance of the group, which is based in Cologne, was unconstitutional and a threat to democracy. They rejected arguments that the ban, originally imposed by Interior Minister Otto Schily in 2001, contravened Germany's guarantee of freedom of religion. Schily welcomed the decision and said he hoped that it would be possible to speed up the extradition process of its leader, Metin Kaplan, who is wanted by Turkish authorities for treason. He is accused of plotting in 1998 to crash an aircraft loaded with explosives into the mausoleum of Kemal Ataturk, the founder of the modern Turkish state. Kaplan's Caliphate State was founded in 1984 in Cologne and before the ban had around 1,100 members.