A Spanish audit office has demanded the former leader of Catalonia and other politicians from the region pay 5 million euros ($5.96 million) for holding a consultative independence ballot in 2014, El Pais newspaper said on Tuesday.
The report, which cited judicial sources, came a day before Catalonia is expected to approve plans to hold an Oct. 1 referendum on a split from Spain.
The 2014 vote was non-binding, a symbolic ballot by pro-independence campaigners that was declared illegal by Spain's Constitutional Court.
Catalonia, along with Britain's Scotland and Belgium's Flanders, has one of the most active independence movements in the European Union.
El Pais said the former head of the Catalan government, Artur Mas and other regional leaders, were being told by the audit body in charge of overseeing the financing of political parties and the public sector to pay out of their own pocket for organizing the consultation vote.
The money was due by Sept. 25, it said.
The audit office was not immediately available for comment.
The current head of the Catalan government, Carles Puigdemont, said the move was the Spanish state "spreading fear."
Catalan lawmakers are due to vote on Wednesday on laws approving the referendum and the legal framework to set up an independent state.
The laws are expected to be approved because pro-independence parties have a majority in the regional parliament.
The populous, north-eastern region, with its capital Barcelona, has a strong national identity with its own language and traditions, although polls show support for self-rule waning as Spain's economy improves.
($1 = 0.8391 euros)