Puigemont's arrest on Sunday sparked widespread protests back in Barcelona, his home base, where crowds gathered in support of a man who led the Catalan independence movement. Dozens have reportedly been injured.

After having followed through on an October referendum to leave Spain, which Spain declared illegal, Puigdemont fled to Belgium where he had been living in exile for the past five months.

Spain at the time had issued a warrant for his arrest but later withdrew it over fears he would claim asylum in Belgium. Belgium is also host to three other exiled Catalan leaders.

Puigdemont was in Finland at the end of last week when the same warrant for his arrest was reactivated by Spanish authorities. He was stopped on the highway in northern Germany after passing through Denmark.

His arrest on Sunday in northern Germany is likely to galvanise support and raise further tensions among separatists who again clashed with riot police in the Catalan capital during the spontaneous protests.

Germany will now have 60 days to decide to extradite Puigdemont. It means figuring out whether the Spanish charges of sedition and rebellion are also punishable under German law.

His Belgium lawyer Paul Bekaert told Reuters that it would likely take months before any final decision is made, given the lengthy legal appeals process.

Spain's supreme court had only days earlier placed Catalan separatist leader Jordi Turull in pre-trail detention, along with other leaders, without the possibility of bail.

All were charged with rebellion and face up to 30-year prison sentences. Turull was set to become regional president after pro-independence parties regained a majority in the parliament.

"No judge, no government and no civil servant has right to charge and pursue the president of all Catalans," Catalan parliament speaker Roger Torrent was quoted as saying in Reuters, following the arrests.