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Roderick Navarro was in class when he got the news that a high-ranking minister had accused him of plotting to assassinate Venezuela's president.

His first thought was, "Not again."

The 26-year-old student leader had already been accused by the ruling socialist party for collaborating with the U.S. to overthrow Venezuela's then-leader Hugo Chavez in 2010. But as messages from friends lit up his phone, Navarro began to worry that it was more serious this time. The denunciation came on live TV, with orders to appear before the national intelligence service.

Announcements of foiled coups and plots against the government have long been a part of the Chavista discourse. A study by the Caracas-based newspaper Ultimas Noticias counted 63 alleged assassination plots between when Chavez took office in 1999 and his death in 2013. Since then, such claims have come even more frequently. President Nicolas Maduro's government has denounced more than a dozen purported plots since coming to power 15 months ago, according to a tally by The Associated Press.

While the Chavez administration tended to point fingers at the CIA or shadowy outside groups, Maduro's accusations often target local opposition figures, who say they face imprisonment, constant surveillance and the threat of vilification or violence from pro-government groups.

The most serious recent allegations came in late May, as authorities tried to mop up dissent that led to a three-month wave of deadly anti-government protests. Top officials accused a handful of opposition leaders of working with the U.S. ambassador in neighboring Colombia to "annihilate" Maduro.

During a news conference that all broadcasters were required to carry live, officials showed heavily annotated slides of emails that they said the plotters had sent each other.

It was a bizarre tableau even by Venezuelan standards, prompting a popular television comic to create a 10-minute spoof. His show was shut down days later in what fans believe was a reprisal, a reminder that the accusations may not be believed by government critics, but can't be laughed off either.

Opponents say the drumbeat of alleged conspiracies helps the administration shift attention away from domestic problems such as soaring prices and rising crime.

The charges against local critics are "one way that the Maduro administration has added extra paranoia to its strategy," said Gregory Weeks, a political science professor specializing in Latin America at the University of North Carolina at Charlotte. "Chavez went after local opposition, too, but he didn't feel the need to use conspiracy theories to do so."

To outsiders, the allegations can seem far-fetched. Chavistas have accused conspirators of using newspaper crossword puzzles to communicate with enemies of the state, of developing tools to give leftist leaders cancer, and of plotting to "ruin Christmas" with a coup. They rarely provide much evidence.

But the charges don't seem that wild to many government supporters, who are well-versed in the history of American plotting against leftist governments from Chile to Cuba during the Cold War and are a quick to recall Washington's endorsement of a coup that toppled Chavez for two days in 2002.

With independent Venezuelan media sources dwindling, people getting their news from television and radio are unlikely to hear much questioning of conspiracy theories.

Fruit vendor Herman Acosta believes the allegations and says the government should do more to protect itself from those who conspire against it.

"I believe the government, because there have been coups all over Latin America and the U.S. has always been the prime actor," he said.

Behind closed doors, diplomats say the accusations make them think twice about what they say in public. In 2008, Chavez kicked out the U.S. ambassador after accusing him of plotting to overthrow the government. This month, a prominent Chavista politician and television host accused the Canadian Embassy of similar meddling.

In the weeks since the May news conference, Maduro's administration has linked an additional two dozen people to the alleged coup attempt, including the editor of El Nacional, which is one of the Venezuelan newspapers most openly critical of the government.

Some of the alleged plotters are trying to prove their innocence.

Pedro Burelli, a former director of Venezuela's state oil company who now lives in Washington, hired a private investigation firm to look into the authenticity of the emails presented in May. The firm said records subpoenaed from Google showed the messages attributed to Burelli had never been sent.

Navarro, the student leader, presented himself for several hours of intelligence service questioning in June, a few weeks after Interior Minister Rodriguez Torres denounced him and several other government opponents. He feared he would be arrested if he didn't show up.

"I was worried because there's no independent justice here," he said.

Navarro is keeping a low profile, working with other students on a plan to re-ignite street protests. He says he is determined not to show fear in the face of the accusations.

But Hugo Perez, a sociology professor at the Universidad Central de Venezuela, says activists have reason to worry. When a government starts talking about opposition plots, any target "is no longer a political adversary — it is the local agent of a foreign conspiracy and therefore an absolute enemy," he said.

For two years, Perez has run a blog devoted to tracking Chavista conspiracy theories. Lately, he's had enough material to post several times a week.

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Hannah Dreier on Twitter: https://twitter.com/hannahdreier

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Associated Press writer Jorge Rueda contributed to this report.