CARACAS, Venezuela -- Venezuela's government has barred opposition leader Henrique Capriles -- twice a major presidential candidate -- from running for office for 15 years, a surprise move sure to ratchet up tensions amid a growing street protest movement

Capriles read from excerpts of the comptroller general's order at a rally Friday night in which he urged supporters to take to the streets, beginning with a previously scheduled demonstration Saturday, to defend their political rights and demand the removal of President Nicolas Maduro.

"When the dictatorship squeals it's a sign we're advancing," he said in a speech surrounded by other leading opposition figures, many of whom themselves have been targeted. "The only one who is disqualified here is you, Nicolas Maduro."

The 44-year-old Capriles has been the most prominent leader of Venezuela's opposition over the past decade, twice coming close to winning the presidency despite institutional obstacles that tilted races in favour of the government. He's currently governor of Miranda state, which surrounds Caracas, and is one of the most recognizable leaders behind the protest movement that has been roiling the country this week.

Maduro didn't comment on the order in an appearance late Friday on state TV, but urged his supporters not to be distracted by tough language coming from "Capriloca," a play on the Spanish word for "crazy." Leaders in the ruling socialist party have accused Capriles in recent days of trying to provoke a bloodbath through his leadership of near-daily protests, many of which have ended in tear gas and rubber bullets

"The right wing's treason of our national interests is cause for indignation," said Maduro.

The move against Capriles is part of a broader government crackdown that began with a decision last week by the Supreme Court to gut the opposition-controlled congress of its last vestiges of power. The move was later reversed amid widespread international condemnation, but with the unpopular Maduro under increasing pressure to call elections, the constant arrests at marches and threats against party leaders may be his best way to stunt the opposition's momentum, analysts said.

"They are trying to raise the costs of protest, plain and simple," said Michael McCarthy, a research fellow focused on Venezuela at American University. "But this move may well backfire, as Capriles is likely to harness this smear campaign to place himself front and centre in the push to hold transition elections."

Authorities have been investigating Capriles since the beginning of the year for what they say are a half dozen administrative irregularities, including taking suspicious donations from abroad.

Among Maduro's opponents, he's considered a moderate, having criticized a wave of protests in 2014 that led to scores of deaths. Those protests ended with the arrest of his main rival within the fractious opposition, Leopoldo Lopez, whose dogmatic politics appeals to hardliners but has often alienated poor voters who backed Hugo Chavez's revolution but are fed up with Maduro's inability to fix widespread shortages and triple-digit inflation.

Capriles is a scion of one of Venezuela's wealthiest families, but his sometimes vulgar talk and mannerisms echo the late Chavez's populist style and he has tried to reach out to Chavez supporters. He prides himself on staying close to home when others in the opposition have been quick to fly off to Washington and other capitals to seek help.

While those divisions over strategy and style haven't gone away, the opposition seems more united than it has for a long time.

This week's protests appear to have claimed their first victim Thursday night. Nineteen-year-old law student Jairo Ortiz was shot dead by a police officer near his home in a poor neighbourhood on the outskirts of Caracas.

The Interior Ministry said that transit police officer had been arrested but denied opposition claims that Ortiz was taking part in any demonstration.