Venezuelan opposition leader Juan Guaido has made his strongest call yet to the military to help him oust President Nicolas Maduro as violence broke out at anti-government protests.
Several dozen armed troops accompanying Guaido clashed with soldiers supporting Maduro at a rally outside the La Carlota air base in Caracas on Tuesday, but the incident fizzled out and did not appear to be part of an immediate attempt by the opposition to take power through military force.
Guaido, in Twitter posts, wrote that he had begun the "final phase" of his campaign to topple Maduro, calling on Venezuelans and the armed forces to back him ahead of May Day mass street protests planned for Wednesday.
"The moment is now!" he wrote. "The future is ours: the people and Armed Forces united to put an end" to Maduro's time in office.
Tens of thousands of people were marching in Caracas in support of Guaido on Tuesday, clashing with riot police along the main Francisco Fajardo thoroughfare.
A National Guard armoured car slammed into protesters who were throwing stones and hitting the vehicle.
Defence Minister Vladimir Padrino called the latest instability a "coup movement" but several hours after Guaido's announcement there was no sign of any other anti-Maduro military activity. Guaido later left a rally he was holding with military supporters at the air base.
Venezuela's Foreign Minister Jorge Arreaza denied there was a military coup attempt under way and accused opposition leader Juan Guaido of operating under orders from Washington.
"It is not a coup attempt from the military. This is directly planned in Washington, in the Pentagon and Department of State, and by Bolton," Arreaza told Reuters in a phone interview from Caracas, referring to US national security adviser John Bolton.
"They are leading this coup and giving orders to this man (Juan) Guaido," he said.
US President Donald Trump said he was monitoring the situation in Venezuela very closely and reiterated US support for its people.
"I am monitoring the situation in Venezuela very closely. The United States stands with the People of Venezuela and their Freedom!" Trump wrote on Twitter.
Repeated opposition attempts to force Maduro, a socialist, from power through huge protests and calls on the military to act have so far failed.
Maduro, a former bus driver who took office after the death of political mentor President Hugo Chavez in 2013, said on Tuesday he had spoken with military leaders and that they had shown him "their total loyalty".
"Nerves of steel!" Maduro wrote on Twitter. "I call for maximum popular mobilisation to assure the victory of peace. We will win!"
The move was Guaido's boldest effort yet to persuade the military to rise up against Maduro.
If it fails, it could be seen as evidence that he lacks the support he says he has. It might also encourage the authorities, who have already stripped him of parliamentary immunity and opened multiple investigations into him, to arrest him.
"Whatever happens now, we won't let ourselves be stopped. Our process is moving on step by step, in accordance with our constitution. We continue to stand for nonviolence," Guaido told German international broadcaster Deutsche Welle in an interview released on Tuesday.
Guaido has said Wednesday's protests will be the largest march in Venezuela's history and part of the "definitive phase" of his effort to take office in order to call fresh elections.