Puigdemont "was arrested today at 11:19 am by Schleswig-Holstein's highway patrol force," a German police spokesman told AFP, adding that the detention was based on a European warrant.

"He is now in police custody", added the spokesman.

Puigdemont's arrest is the latest chapter in a secession saga that has bitterly divided Catalans and triggered Spain's worst political crisis in decades.

It also came two days after Spain's supreme court said it would prosecute for "rebellion" 13 Catalan separatists, including Puigdemont and his nominated successor Jordi Turull, over their role in the region's failed bid for independence.

If found guilty, they face up to 30 years in prison. Twelve more face less serious charges such as disobedience.

Issuing an international arrest warrant for Puigdemont on Friday, Judge Pablo Llarena accused the ousted Catalan leader of organising an independence referendum in October last year despite a ban from Madrid and "grave risk of violent incidents".

The vote had been swiftly followed by the Catalan parliament's declaration of independence on October 27.

As Spanish authorities moved in to impose direct rule over the region, Puigdemont and four other deputies subsequently fled to Belgium.

While separatist parties won Catalonia's regional elections in December called by Madrid, they have been unable to form a government for the region as they chose candidates who are either in exile or in jail or facing prosecution over the separatist drive.

Puigdemont who had run in December's polls from Belgium announced in March that he was abandoning his bid to return as regional president, as he faced arrest if he returned to Spain.

- On the way to Belgium -

He had been visiting Finland since Thursday, but slipped out of the Nordic country before Finnish police could detain him on the warrant issued Friday.

Separately confirming his arrest in Germany, Puigdemont's party spokeswoman Anna Grabalosa said: "It happened as he crossed the Danish-German border. He was treated well and all his lawyers are there. That is all I can say."

Puigdemont's lawyer Jaume Alonso-Cuevillas, said on Twitter that the ex-Catalan leader was picked up by German police as he was travelling back to Belgium to "present himself, as always, at the disposal of Belgian courts".

Focus magazine reported without citing its sources that German police were tipped off about Puigdemont's movements by Spanish intelligence services who had been tracking him.

German authorities have 60 days to decide whether to extradite Puigdemont to Spain.

"We will first examine the extradition conditions, and then we'll look at anything further," Ralph Doepper, leading prosecutor at Schleswig Holstein's prosecution service, told NDR broadcaster.

National news agency DPA quoting unnamed sources said Puigdemont was driven in a small van with tinted windows to a prison at Neumuenster.

Elsa Artadi, a spokeswoman for Puigdemont's Together for Catalonia party, said that he should fight his extradition to Spain as she argued that he would not get a fair trial in the country.

"Spain does not guarantee a fair trial; only revenge and repression," she wrote on Twitter.

- 'Respond together' -

Hardcore separatists, the radical Committees for the Defence of the Republic (CDR), called a protest against Puigdemont's arrest.

"Faced with this serious situation, we must respond together," the CDR said on Twitter, urging protesters to gather on the city's main boulevard, Las Ramblas, at 4 pm (1400) and outside central government offices in the city three hours later.

In Girona, about 100 kilometres (60 miles) north of Barcelona, dozens of people were protesting outside the offices of Spain's central government representative in Catalonia, according to images posted by the CDR on Twitter.

They painted the building's facade in yellow, the symbolic colour of Catalan separatists.

Albert Rivera, the leader of the centrist party Ciudadanos which was set up in Catalonia to fight against separatism, welcomed Puigdemont's arrest, saying the justice system was "doing its job".

"The flight of the coup leader Puigdemont is over. Trying to destroy a European democracy, bypassing democratic laws, breaking up coexistence or misusing public money cannot enjoy impunity. The justice system is doing its job," he tweeted.

The Supreme Court's decision this week to prosecute the group of separatists has also sunk the Catalan parliament deeper into a quagmire as its latest regional presidential candidate Jordi Turull was placed in custody over the breakaway bid.

That marks the third time that parliament has been thwarted in its bid to nominate a new president.

After Puigdemont was forced to withdraw his bid for the presidency, another pro-independence leader Jordi Sanchez followed suit when a judge refused to let him out of jail to be sworn in.

Fresh regional elections will be triggered if a new leader is not elected by May 22.afp