Thousands of demonstrators walk behind a banner reading "Vote to Decide. Democracy. Catalonia, We Are With You" during a march organised by pro-Basque independence organization Gure Esku Dago (In Our Hands) in favour of a planned referendum on the independence of Catalonia, in Bilbao, Spain, September 16, 2017. REUTERS/Vincent West

BARCELONA (Reuters) – More than 700 mayors from across Catalonia gathered in Barcelona on Saturday to confirm their support for a planned independence referendum that Madrid has declared illegal.
The Catalan government plans to hold a referendum on self rule for the wealthy northeastern region on Oct. 1, despite strong opposition from government which has challenged the vote in the Constitutional Court.
The mayors met with Catalonia’s regional head Carles Puigdemont in a show of defiance, following Spanish prosecutors warning earlier this week that officials engaging in any preparations for the vote could be charged with civil disobedience, abuse of office and misuse of public funds.
On Wednesday, Spanish prosecutors summoned for questioning more than 700 mayors who had said they would allow municipal spaces to be used for voting. If the mayors do not respond to the order, police should arrest them, the order said.
Meeting in downtown Barcelona …