Exiled former Catalan president Carles Puigdemont, who was arrested in Sardinia at Spain's request, will be freed while he challenges his extradition but must stay on the island, his lawyer said on Friday.

Lawyer Agostinangelo Marras told reporters outside the court in Sassari that Mr Puigdemont had appeared at a hearing via videolink from jail, where he spent the night following his arrest on the Italian island on Thursday.

Although the judge has not yet ruled on his bail conditions, Mr Marras said prosecutors had not asked for him to be detained and "he could be released from today".

Carles Puigdemont, who is a member of the European Parliament, is wanted by Madrid on charges of sedition over his attempts to lead a Catalan breakaway from Spain in October 2017, which sparked the country's worst political crisis in decades.

His lawyers are challenging the validity of the arrest warrant, a process that Mr Marras said could take "some weeks".

Mr Puigdemont's arrest came a week after the left-leaning Spanish government and regional Catalan authorities resumed negotiations to find a solution to Spain's worst political crisis in decades.

In March, the European Parliament rescinded immunity for Puigdemont and two other pro-independence MEPs, a decision that was upheld in July by the EU's General Court.

However, the European Parliament's decision is under appeal and a final ruling by the EU court has yet to be made.

Following yesterday's arrest, Madrid expressed "its respect for the decisions of the Italian authorities and courts".

'Persecution'

New Catalan president Pere Aragones - a separatist but more moderate than his predecessor - condemned what he called the "persecution" of Mr Puigdemont.

"In the face of persecution and judicial repression, the strongest condemnation. It has to stop," he wrote on Twitter.

He added that "self-determination" was the "only solution".

Quim Torra, who took over the presidency in 2018 following the referendum, described Mr Puigdemont's possible extradition to Spain as "catastrophic" and called on pro-independence activists to be "on high alert".

The October 2017 referendum was held by Catalonia's separatist regional leadership despite a ban by Madrid and the process was marred by police violence.

A few weeks later, the leadership made a short-lived declaration of independence, prompting Mr Puigdemont to flee abroad.

Others who stayed in Spain were arrested and tried.

However, Mr Puigdemont did not benefit from the pardon granted in June to nine pro-independence activists who had been imprisoned in Spain.