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 armed men in military uniform near the La Carlota air force base in Caracas.

The government promptly dismissed any suggestion of a military insurrection.