The president of Spain's powerful northeastern region of Catalonia on Saturday formally called an independence referendum, the latest secession push in Europe and one of the most serious challenges to the Spanish state in recent years.
Catalan leader Artur Mas signed the decree to call the referendum in a solemn ceremony in the regional government headquarters in Barcelona, flanked by most of the region's political leaders who support the vote.
"Like all the nations of the world, Catalonia has the right to decide its political future," said Mas.
Two hours after Mas spoke, Deputy Prime Minister Soraya Saenz de Santamaria said the Spanish government will hold an emergency cabinet meeting within days so the referendum can be challenged before Spain's Constitutional Court.
"This referendum will not be held because it is unconstitutional," she told reporters during a rare Saturday press conference.
Pro-independence sentiment in the economically strong region, where the Catalan language is spoken side-by-side with Spanish, has surged in recent years, fueled by a sense that the region deserves better fiscal and political treatment from Madrid.
The announcement came a week after Scotland voted against breaking away from Britain.
Prime Minister Mariano Rajoy was flying back from a state visit to China when Mas made his declaration. He has repeatedly said Spain's constitution doesn't allow referendums on sovereignty that don't include all Spaniards, and experts say the Constitutional Court is almost certain to declare the vote illegal.
While Mas called the referendum, hundreds of pro-independence supporters gathered in the square in front of the Catalan government building in the center of Barcelona, with many wearing or waving pro-independence flags and chanting "independence." The crowd cheered when an electronic clock counting down the days until the referendum was set in motion on the side of a building overlooking the square.
"Today is a day to celebrate. We are very happy and satisfied that president Mas has called the referendum," said Carme Forcadell, the leader of a pro-independence group that has pushed for the referendum by organizing rallies over the past three years.
Unlike the Scotland vote, a pro-secession result in a referendum in Catalonia wouldn't result directly in secession but Mas says it would give him a political mandate to negotiate independence.
In the referendum, Mas wants to ask Catalans two questions; first, if they think Catalonia should be a state, and, if so, should it be independent. If the referendum is not held, Mas could call early regional elections that would essentially serve as a Yes or No vote on independence.
Polls indicate most Catalans favor holding the referendum but are roughly evenly split on independence. Pro-independence fervor fades when people are asked if they favor an independent Catalonia outside the European Union, as the region has been warned would happen.
The referendum has stirred debate about whether the 1978 Spanish Constitution should be updated to accommodate Catalonia's demands for more power while maintaining the 17-region country unified. Separatist sentiment is also very strong in the northern Basque region.
Giles and Associated Press writer Alan Clendenning contributed from Madrid.