- Venezuelan opposition leader Juan Guaido said on Tuesday he had begun the "final phase" of his plan to oust President Nicolas Maduro.
- He called on Venezuelans and the military to back him to end Maduro's "usurpation."
- Guaido, in a video posted on his Twitter account, was speaking in the company of men in military uniform and opposition politician Leopoldo Lopez.
Venezuelan opposition leader Juan Guaido said on Tuesday he had begun the "final phase" of his plan to oust President Nicolas Maduro, calling on Venezuelans and the military to back him to end Maduro's "usurpation."
A Reuters journalist later saw security forces firing tear gas at Guaido and around 70 mostly young armed men in military uniform outside the La Carlota air force base in Caracas. Hundreds of civilians also joined the group.
But around two hours after Guaido tweeted his announcement, there was no sign of any other military activity, and the government dismissed any suggestion of an insurrection.
"We reject this coup movement, which aims to fill the country with violence," said Defense Minister Vladimir Padrino.
He said the armed forces remained "firmly in defence of the national constitution and legitimate authorities," and that all military units across Venezuela "report normality" in their barracks and bases.
The move was Guaido's boldest effort yet to convince the military to rise up against Maduro. If it fails, it could be seen as evidence that he lacks the support he claims to have.
It might also encourage the authorities, which have already stripped him of parliamentary immunity and opened multiple investigations into him, to arrest him.
The United States is among some 50 countries that recognise Guaido as Venezuela's president, and has imposed sanctions to try to dislodge Maduro.
Oil prices topped $73, partly driven higher by the uncertainty in Venezuela, an OPEC member whose oil exports have been hit by U.S. sanctions and an economic crisis.
Trump "Has been briefed"
U.S. President Donald Trump "has been briefed and is monitoring the ongoing situation," White House spokeswoman Sarah Sanders said.
The White House declined comment on whether the administration had been consulted or had advance knowledge of what Guaido was planning.
A former U.S. official said that while it was unclear whether Guaido's efforts would touch off a broader military uprising against Maduro, it appeared aimed at building momentum toward Wednesday's May Day Street protests and making that a turning point.
Venezuelan Information Minister Jorge Rodriguez tweeted that the government was confronting a small group of "military traitors" seeking to promote a coup. Diosdado Cabello, head of the Constituent Assembly, a legislative body that acts in support of the government, said the opposition had not been able to takeover the air base.
He urged Maduro's backers to rally at the presidential palace in Caracas to support him.
Guaido, in a video posted on his Twitter account, was accompanied by men in military uniform and opposition politician Leopoldo Lopez, who has been placed under house arrest.
"The national armed forces have taken the correct decision, and they are counting on the support of the Venezuelan people," Guaido said.
Guaido, the leader of Venezuela's opposition-controlled National Assembly, in January invoked the constitution to assume an interim presidency, arguing that Maduro's re-election in 2018 was illegitimate.
He has been traveling outside the capital Caracas in recent weeks to try to put pressure on Maduro to step down.
Anti-Maduro protests are planned for Wednesday, including what Guaido has said will be "the largest march in Venezuela's history," part of what he calls the "definitive phase" of his effort to take office in order to call fresh elections.
But Maduro, for his part, has appeared to retain control of state institutions and the loyalty of senior military officers.
He has called Guaido a U.S-backed puppet who seeks to oust him in a coup. The government has arrested his top aide, stripped Guaido of his parliamentary immunity and opened multiple probes. It has also barred him from leaving the country, a ban Guaido openly violated earlier this year.
Last week, Guaido said his congressional ally - opposition lawmaker Gilber Caro - had been detained, and that 11 members of his team had been summoned to appear before the Sebin intelligence agency.
Lopez, seen with Guaido, appeared to have left his home for the first time since being placed under house arrest in 2017, after three years in jail.
"I have been freed by soldiers on the side of the constitution and President Guaido," he tweeted. All of us have to mobilize. It's time to win our freedom."
A soldier in the group with Guaido, who identified himself just as Rivas, denied government accusations that they had been tricked into backing Guaido.
"We're all afraid," he told Reuters, "but we had to do it".
Spain, the former colonial power in Venezuela and instrumental in setting the European Union line, said that, although it considered Guaido the legitimate leader of Venezuela, it did not support a military coup and wanted to see elections.