Spanish police arrested nine activists on Monday linked to Catalonia's pro-independence movement who may have been preparing violent actions, seizing material that could be used to make explosives.
The movement calling for Catalonia's separation from Spain has been a major challenge for the country for years, triggering its biggest political crisis in decades with a short-lived independence declaration in 2017.
However, it has largely been a peaceful movement characterized by mass protests, in contrast to a Basque separatist campaign that was for decades marked by a violent insurgency until ETA (Basque Homeland and Liberty) guerrillas ended their fight in 2018.
Police said the investigation and raids targeted local groups working under the name Committees for the Defence of the Republic (CDR), which have staged periodic protests across Catalonia since separatist leaders were arrested after the 2017 independence declaration.
"So far, nine arrests have been made and 10 raids have been carried out in the province of Barcelona, with the purpose of locating and, where appropriate, seizing evidence of the degree of preparation of violent actions," police said in a statement, adding that more arrests could be made.
La Vanguardia newspaper said the raids started at 5 a.m. (0300 GMT) in various towns in Catalonia, including Sabadell and Parets del Valles.
Documents, computer hardware were seized, police said.
"In addition, we have found abundant material and substances which are considered precursors for the manufacture of explosives, susceptible (pending confirmation by specialists) of being used in the manufacture of explosive devices."
Catalonia's independence is reaching a turning point with a verdict expected in the first half of October in the trial of 12 separatist leaders for their role in the 2017 independence referendum and declaration.
A poll published in July by a public Catalan institute showed support for an independent Catalonia at its lowest level in two years, with 48.3% of people against and 44% in favour.