Spain's constitutional court announced last night that it is blocking former Catalan leader Carles Puigdemont from returning to power in the region while he remains the subject of legal action.
The court said in a statement that its 12 magistrates had decided unanimously "to preventively suspend the investiture of Puigdemont unless he appears in the (regional) parliament in person with prior judicial authorisation".
Mr Puigdemont, who fled to Belgium after the Catalan parliament declared independence in October, was earlier this week chosen as a candidate to lead Catalonia again, with the regional parliament set to vote for a new leader on Tuesday in Barcelona.
However, he faces arrest for rebellion, sedition and misuse of public funds over his attempt to break Catalonia away from Spain as soon as he returns to the country.
Mr Puigdemont has said he could be sworn in to office remotely via video conference from Brussels, a plan Spain's central government opposes.
He has also said he would rather return to Spain, but without any risk of arrest.
The constitutional court warned all members of the Catalan parliament of "their responsibilities" and warned against disobeying the order to suspend any investiture.
The magistrates said they needed six more days to consider a government bid to annul the nomination of Mr Puigdemont as a candidate for the regional presidency.
"The government must use every tool made available by the laws and the constitution to make sure that a fugitive, someone who is on the run from the law and the courts, cannot be illegitimately be sworn in," Spain's Deputy Prime Minister Soraya Saenz de Santamaria said after the government lodged the legal bid to keep Mr Puigdemont from returning to power.
After the court's announcement, Mr Puigdemont tweeted that "even the constitutional court has rejected the tricks of Moncloa," referring to the prime minister's official residence.
Prime Minister Mariano Rajoy said that "the government would continue to do its duty in respecting the law".
Catalonia's ousted separatist government pushed ahead with an independence referendum on 1 October despite it having been banned by the Constitutional Court.
It won the public vote but Catalonia's independence declaration on 27 October was short-lived as Mr Rajoy moved to stop the crisis in a region deeply divided over secession.
He imposed direct rule on the semi-autonomous region, sacked its government including Mr Puigdemont, dissolved its parliament and called snap elections.