BARCELONA, Spain - Spanish police said Thursday they have arrested a man who they believe intended to attack Spanish Prime Minister Pedro Sanchez over his controversial decision to exhume the remains of late dictator Gen. Francisco Franco.

Police say the 63-year-old former private security guard was arrested in the town of Terrassa in the Catalonia region on Sept. 19 after a brief investigation. He remains in custody and has not been charged.

The case was revealed Thursday by Spanish newspaper Publico.

Police said they found 16 firearms in the suspect's home, ranging from handguns to sniper rifles, but did not explain how he had managed to amass such an arsenal.

“This person had a clear intention and will to take actions against the prime minister,” Catalan regional police spokesman Albert Oliva told journalists. He added that the suspect did not appear to have concrete plans, but had been asking for logistical support on a WhatsApp group chat.

According to Oliva, the suspect wrote in one of the messages that he was “willing to sacrifice (himself) for Spain” and that he showed no concern over the legal consequences of carrying out an attack.

Police say the investigation was launched after an unidentified person who had read the suspect's messages alerted them.

The far-right VOX party, which opposes the exhumation of Franco, issued a statement Thursday saying one of its local co-ordinators informed police of the suspect's plans after reading them on a WhatsApp group chat. VOX said the suspect was not affiliated to the party.

Spain's centre-left government decided earlier this year to exhume Franco's remains from a self-aggrandizing mausoleum, but officials have struggled to find an appropriate new burial place.

Relatives and supporters of the late dictator oppose the exhumation. If the government goes ahead, Franco's family wants his body reinterred under Madrid's cathedral - a move that could undermine efforts to rid the country of his long shadow.

Sanchez on Thursday thanked police for their work and said that he was grateful for the show of support he received.

The government played down the suspected plot, calling it an isolated incident.

“Every government has experienced incidents like this,” government spokeswoman Isabel Celaa told reporters after the weekly cabinet meeting.