Madrid (AFP) - A woman was arrested Tuesday for "rebellion" and "terrorism" in a probe of pro-independence activists in Catalonia who have staged protests such as road blockades, the interior minister said.
"There is one arrest, a woman," Juan Ignacio Zoido told Spanish television.
"But the operation is still ongoing, and it's true they are accused of rebellion and terrorism."
It was the first arrest for "terrorism" of a member of the radical pro-independence activist groups called the Committees for the Defence of the Republic (CDR) which formed last year before an independence referendum on October 1.
Spain's National Court, which deals with major cases including those that are terror-related, is in charge of the probe, said the minister.
The public prosecutor's office said the investigation targeted a man and a woman but police had so far only arrested the woman.
Hundreds of people, many waving red-and-yellow striped Catalan independence flags, protested against the police operation outside of Barcelona city hall on Tuesday night, images on Spanish TV showed.
Smaller protests were also held in other Catalan cities including Girona, Tarragona and Lleida, in response to an appeal on Twitter by the CDR.
Zoido said the CDR "started to wage violent acts before and during the (independence) process".
On the day of the vote, which went ahead despite a court ban, hundreds of activists posted themselves in front of polling stations. Police dislodged them, sometimes violently.
In recent weeks, the groups have protested against the jailing of more pro-independence leaders and the detention of former Catalan president Carles Puigdemont in Germany. The leaders have been prosecuted over their role in a failed bid to secede from Spain last October.
At the end of March, the protesters blocked major roads in Catalonia and tried to occupy the central government's representative office, heavily guarded by police, on several occasions. The resulting clashes left dozens injured.
- 'Trivialise terrorism' -
Puigdemont criticised the arrest by tweeting a definition of terrorism as being "a political movement that uses terror based on violence as a means of pressure".
The operation was also criticised by Inigo Errejon, a lawmaker with the far-left party Podemos, who said it was "not appropriate for anyone to trivialise" the charge of terrorism.
"In Spain, we know well, unfortunately, what terrorism is," he tweeted in a reference to the Basque separatist ETA which is blamed for the deaths of more than 800 people in its long campaign of bombings and shootings for an independent Basque homeland.
Spain has also witnessed several Islamist terror attacks in the past decade-and-a-half, the most recent coming in August in Barcelona, when a vehicle ploughed into crowds, killing 14 people.
Puigdemont and others have already been charged with rebellion, which carries up to 30 years in jail.
The use of this charge has raised controversy as it implies violence took place, which independence supporters and several judges and lawyers say didn't happen.
In Germany, a court ruled that Puigdemont would not be extradited to Spain on a rebellion charge.