German prosecutors filed a request to a regional court for the extradition of the former regional president of Catalonia, Carles Puigdemont, to Spain to face charges of inciting a rebellion and sedition in connection to the separatist leader’s illegal bid to declare Catalonia’s independence from the rest of Spain.

Puigdemont has been held in a detention centre in the northern German town of Neumuenster for just over a week after he was arrested after entering the country on March 25.

“This has a comparable equivalent in German law,” said the prosecutors in a statement. The prosecutors also asked that Puigdemont remains in jail given that he is a flight risk after he secretly fled to Brussels in the wake of his failed attempt to form a separatist state.

“The accusation of rebellion essentially contemplates the holding of an unconstitutional referendum even though violent confrontations were to be expected,” said the prosecution’s statement.

Puigdemont fled Spain five months ago for Belgium after Spanish Prime Minister Mariano Rajoy dismissed his regional administration and imposed direct rule on Catalonia from Madrid. Puigdemont could face up to 25 years behind bars if he is found guilty of having led an illegal secession referendum.

Puigdemont’s German lawyer, Wolfgang Schomburg, said he would file an appeal with the German government to have the ex-Catalan nationalist leader freed, a move that could be vetoed by the country’s justice minister.

German prosecutors have said the accusation by Madrid that the bookish Puigdemont misused of public funds to carry out an unconstitutional referendum also had an equivalent in German law.

A lawyer by training, Puigdemont has continued to reject the charge of inciting a rebellion in Spain’s Supreme Court, saying he did not commit any acts of violence and did not illegally use Spanish government funds to finance a secessionist vote.

The Spanish government is currently trying 25 Catalan nationalist leaders who were involved in the October 2017 secessionist vote. International arrest warrants are active against four other politicians who fled abroad last year, including Carla Ponsati, a former Catalan education minister and nationalist leader, who is fighting extradition from her current place of residence in Scotland.

Five separatist leaders are in custody and awaiting trial in Spain; all have denied any wrongdoing.

The Catalan separatist leadership, including Puigdemont, claim they will not be given a fair trial in Spain and are being prosecuted for their political beliefs.

Madrid, however, says they violated the Spanish constitution when forging ahead with an internationally unrecognised vote on independence and are subject to prosecution under the law.