Spain's state prosecutor ordered local authorities to investigate 712 pro-independence mayors in Catalonia on Wednesday, and for police to detain mayors who do not cooperate.
This latest order comes amid growing tension between Madrid and Barcelona because of a proposed independence referendum on Oct. 1, which has been deemed illegal by Spanish courts.
Wednesday's order instructs local authorities to summon the mayors to testify in court. Where mayors refuse to testify, the authorities are instructed to "arrange his or her detention and presentation to the Prosecutor".
The mayors in question have all publicly pledged their support for the referendum and they represent around 75 percent of all Catalan mayors.
"We reiterate our maximum support of all the mayors. Defending democracy can never be a crime," tweeted the Association of Municipalities for Independence, the organization that published the list of pro-independence mayors the authorities are now investigating.
On Tuesday, police were summoned to a Catalan court and ordered to seize any material related to the independence referendum.
Still, the pro-independence government in Catalonia says the vote will go ahead.
As tensions over the independence referendum reach record heights, Spain's King Felipe VI made his first public statement since Catalonia's government passed a bill in their parliament that details the referendum and established an "exception judicial regime" in the wealthy north-eastern region of Spain.
This bill has since been suspended by Spain's Constitutional Court, however.
"Against those who are outside of constitutional legality… I am sure that the laws that pertain to all Spaniards will be preserved," the monarch said on Wednesday at the National Culture Awards in Cuenca.
