Ousted Catalan leader Carles Puigdemont called on Saturday for a united political front in the Dec. 21 election to continue the drive for independence from Spain and to protest the imprisonment of former members of the regional government.
Puigdemont, who went to Belgium after his government was fired following a unilateral declaration of independence, said on Friday he was considering standing in the election from Brussels.
In Spain's gravest political crisis since the return of democracy in the late 1970s, Prime Minister Mariano Rajoy called the snap election after taking control of Catalonia a week ago.
Political parties in the wealthy northeastern region that wish to run on a common platform have until Tuesday to register any potential coalition.
"It is time for all democrats to join together. For Catalonia, for the freedom of political prisoners and for the republic," Puigdemont said in a tweet that included the hashtag llistaunitaria.cat, a site calling for parties to unite against the Spanish government at the ballot box.
On Thursday, nine members of Puigdemont's sacked cabinet were ordered by Spain's High Court to be held on remand pending an investigation and potential trial.
On Friday, Spain issued an arrest warrant for Puigdemont and four associates to answer charges of rebellion, sedition, misuse of public funds, disobedience and breach of trust relating to their secessionist campaign.