MADRID (AP) — Spain's Supreme Court barred Monday Catalonia’s regional president from his office for refusing to remove a banner that called for the release of imprisoned separatist leaders and was displayed on a public building ahead of the 2019 general election.

The ruling that Quim Torra disobeyed Spain's electoral law triggers a new period of uncertainty in the northeastern Spanish region. According to the existing regulations, Torra’s deputy should take over as president-in-charge until a new election is held.

Pro-secession activists reacted by calling for protests later on Friday in the regional capital, Barcelona.

In their ruling, the panel of judges unanimously agreed to confirm last year's decision by a lower court to ban Torra from holding any public office for 18 months and fine him 30,000 euros ($35,000).

Torra, a staunch separatist who became the head of Catalonia’s government following the 2017 push for the region’s independence from Spain, had previously criticized the case as an act of repression against the democratic mandate of voters in the region.

He had remained at the helm of Catalonia during the appeal but Monday's decision must be implemented even if the case is taken to the European Court of Human Rights, as pledged by Torra's defense team.

The banner at the center of the case referred to a dozen former Catalan Cabinet members, lawmakers and activists who were imprisoned or fled Spain following a declaration of independence in October 2017.

The court on Friday said that Torra had “stubbornly” disobeyed the country’s electoral board by refusing to take it down from a balcony in the regional government's headquarters.

In hearings, Torra and his defense lawyers had argued that he was defending the higher cause of political and human rights. But the Supreme Court judges said that the electoral board's order didn't violate Torra's right to free speech and only limited what he could do in his role as an elected official.

Torra, who has in the past encouraged acts of civil disobedience in response to Spanish judicial rulings, didn’t react immediately to the ruling.