Carles Puigdemont intends to become leader of the world's newest independent state next week. Instead, he may spark a violent confrontation with Spanish authorities and wind up in jail.

Puigdemont, 54, a former journalist and president of Spain's semi-autonomous region of Catalonia in northeastern Spain, vowed Thursday to press ahead with an independence referendum on Sunday despite efforts by the national government to block it.

"It's very clear to me that if I go to prison over this it's only because of my political beliefs. That would leave Spanish democracy in a very weak position," Puigdemont told USA TODAY in a phone interview Thursday. "As president, I have the right to call a referendum based on a law that the Catalan parliament has approved. The vote will go ahead."

The central government in Madrid insists the vote is illegal and has taken steps to block it. It has seized millions of ballots, detained 14 senior officials organizing the vote, shut down election websites and deployed thousands of police to bar access to voting stations.

The vote is the most serious political crisis facing Spain since it returned to democracy following the death of longtime military dictator Francisco Franco in 1975.

The independence drive is fueled by the belief that Catalonia and its tourist-mecca capital, Barcelona, give more than they get from Madrid and that the region's unique culture and language are not respected by the Spanish state, according to Puigdemont.

The wealthy region, where 7.5 million of Spain's 46 million people live, accounts for approximately one-fifth of the country's economy. It is one of 17 semi-autonomous Spanish regions.

If the vote takes place, and passes convincingly, Puigdemont has said he would announce a split from Spain within 48 hours. Two years ago, 80% of Catalan voters backed independence in a symbolic vote, but turnout was less than 40%, muddying its conclusiveness.

An opinion poll from July showed 49% of Catalans oppose independence to 41% in favor. Nationally, most Spaniards, who aren't eligible to vote, oppose a separate state.

The United Kingdom's government allowed Scotland to hold an independence referendum in 2014 and the measure lost, with 55% of Scots preferring to remain part of Britain.

By contrast, Spanish Prime Minister Mariano Rajoy insists the Catalonia vote "won't happen." Speaking alongside President Trump at the White House on Tuesday, he said it would be "ridiculous" if Catalonia declares independence. Trump agreed. "I think the people of Catalonia should stay with Spain. I think it would be foolish not to," Trump said.

Jose Manuel Maza, Spain's top public prosecutor, said if the vote does occur, Puigdemont could be charged with civil disobedience and for misusing public funds. The latter offense carries a prison sentence of up to eight years.

Catalonia's push for independence gained momentum during the country's financial crisis, said Neil Davidson, a political scientist at the University Glasgow who studies independence movements. Spain's economy has recovered about a third of the 3 million jobs it lost during the depth of the 2008 recession, but its unemployment rate is still at 18%.

"Catalans have this feeling that they would simply be better off on their own," he said.

In the interview, Puigdemont said he is concerned the Madrid government might deliberately inflame tensions with a provocative action. It would be "highly suspicious" if "somehow, at a time when Madrid has put thousands of police on our streets, an incident happens," he said.

Alex Ramos, a doctor and vice president of Catalan Civil Society, an organization against independence, said there is little difference between Catalonians and Spaniards, and the referendum is not a realistic solution to economic or cultural grievances.

"Spain's different regions are like a family. And families don't split up by tossing a coin in the air and seeing how it lands," he said

Antonio Barroso, a Spanish national who analyzes European economic and political affairs in London for the consulting firm Teneo Intelligence, questioned whether the real purpose of the vote is to gain concessions from Madrid.

"We know that independence won't happen," he said. "Even if Puigdemont and his allies declare independence unilaterally, nobody — not Spain, not the European Union — will recognize Catalonia as an independent state. He knows that. This is the reality."

Puigdemont expressed frustration that the EU has not done more to support what he called the "violation of fundamental rights in Catalonia." He said Madrid's crackdown on the vote means Catalans are being "deprived of the freedom of speech," but the EU is "not saying anything about this at all."

Earlier this month, Jean-Claude Juncker, the president of the European Commission, the bloc's executive arm, said the Spanish government's decisions should be respected.

On Thursday, two United Nations rights experts criticized the Spanish authorities.

"Regardless of the lawfulness of the referendum, the Spanish authorities have a responsibility to respect those rights that are essential to democratic societies," David Kaye and Alfred de Zayas said in a statement. "The measures we are witnessing are worrying because they appear to violate fundamental individual rights, cutting off public information and the possibility of debate at a critical moment for Spain’s democracy."

Puigdemont said that he did not know of any country, including the United States, that had exercised the right to self-determination and then regretted it.

"Therefore, it must be a good thing," he said.