Carles Puigdemont, the former president of Catalonia, has been detained by German police after crossing the border from Denmark, reports the BBC. German police were acting on a European arrest warrant; Puigdemont is wanted in Spain on charges of sedition and rebellion that could see him imprisoned for 30 years. Puigdemont has been in self-imposed exile in Belgium since November, and was returning there from a trip to Finland when he was arrested. "The president was going to Belgium to put himself, as always, at the disposal of Belgian justice," a rep says. Things are again heating up in Catalonia, with Spain's Supreme Court ruling Friday that 25 Catalan leaders should be tried on charges ranging from rebellion to embezzlement. That ruling reactivated Puigdemont's arrest warrant, catching him off-guard while giving a university lecture. (More Carles Puigdemont stories.)