Spain's state prosecutor has summoned more than 700 Catalan mayors who have backed an independence referendum, in an escalation of Madrid's efforts to block the vote that it has declared illegal.
Officials engaging in any preparations for the vote could be charged with civil disobedience, abuse of office and misuse of public funds, the prosecutor said in a letter delivered to local authorities on Wednesday.
If the mayors do not answer the summons, police should arrest them, it added.
One mayor said the legal move was unprecedented.
"We don't think any European country has ever tried to make more than 700 mayors testify," said Neus Lloveras, mayor of Vilanova i la Geltru near Barcelona, head of the Association of Municipalities for Independence (AMI).
"We have nothing to hide. When we have to go and testify, we will say everything we have been saying for days, that we owe it to our people to keep working to make sure they can freely express themselves at the ballot box," he told reporters.
But the small, anti-capitalist CUP group, which governs 19 Catalan municipalities, said it would not answer the summons, and called on other political forces to do the same.
Catalonia's regional parliament passed laws last week to prepare for a referendum on Oct. 1. Spain's Constitutional Court suspended the vote after Prime Minister Mariano Rajoy challenged it in the courts.
Judges are now considering whether the legislation contravenes Spain's constitution, which states that the country is indivisible.
So far, 712 of a total 948 municipal leaders have said they would allow public spaces to be used for the referendum, according to AMI.
The mayor of Barcelona — the region's most populous area — has yet to take a definitive position, and has asked for reassurances that civil servants involved in the process will not risk losing their jobs.
Website stops working
The website set up by the Catalan government to give information on the vote, referendum.cat, stopped working Wednesday evening, with Spanish media reporting that the regional prosecutor had ordered all websites promoting the referendum to be shut down.
Civil Guard police confirmed that they had gone to deliver a warrant at the website's offices, but declined to say if judges had ordered it to be closed.
Catalan leader Carles Puigdemont quickly posted two new web addresses on Twitter linking to a page with information on the referendum.
Polls show a minority of Catalans want self-rule, although a majority want the chance to vote on the issue. Hundreds of thousands of people took to the streets of Barcelona this week to show support for independence.
In a separate order, the Constitutional Court told regional government officials on Wednesday they had 48 hours to show how they were preventing the vote from going ahead.