A court on Tuesday summoned Catalonia`s president for questioning over an allegedly illegal 2014 ballot on independence from Spain, raising pressure on separatists after they won control of their regional parliament.
The move by the Catalonia high court came as a bitter standoff between Mas and the Spanish government deepened after he and his separatist allies declared victory in Sunday`s regional election.
Buoyed by that result, the separatists vowed to push on towards a declaration of independence by 2017 but Madrid promised to defend the unity of Spain.
Two days after the regional vote, in a judicial investigation dating back to last year, the court on Tuesday called Mas to go before a judge with a view to possible charges.
Prosecutors have accused him of civil disobedience, abuse of power and embezzlement of public funds for pressing ahead with the vote.
The court summoned him for questioning on October 15, in a written ruling released on Tuesday. It summoned two other members of his former regional administration to appear on October 13.
Mas is accused of breaking the law by organising the earlier ballot on November 9, 2014, in defiance of an injunction by Spain`s Constitutional Court.
Mas wanted his rich northeastern region to follow the example of Scotland by holding a referendum on independence.
The Constitutional Court`s ban forced him to water down his plan for an official vote. Instead the November 9 ballot was merely symbolic and organised by volunteers.
He later called the snap regional election on September 27 and campaigned in a pro-independence alliance.
That group won enough seats in Sunday`s vote to control the regional parliament if it teams up with the radical left-wing movement CUP.
Both groups said they would start this week holding meetings to discuss how to proceed towards a declaration of independence.
Spain`s Prime Minister Mariano Rajoy repeated however that he would not negotiate on demands for independence.
Three months ahead of a general election, Rajoy is vowing to preserve unity in Spain, the eurozone`s fourth-biggest economy, as it recovers from an economic crisis.