Maduro, whose last two re-elections were rejected as fraudulent by the United States and other countries, fears the naval deployment is a regime-change plot under the guise of an anti-drug operation.

Nobel laureate Machado has welcomed the military presence -- which has seen strikes on alleged drug boats claim at least 83 lives in the Caribbean and Pacific -- and backed Washington's claim that Maduro heads a drug cartel.

US President Donald Trump said recently that he believed Maduro's days were numbered and on Monday refused to rule out boots on the ground -- though he was open to talks with the leftist South American leader.

"We are on the threshold of a new era," Machado, the 2025 Nobel Peace Prize winner, said in a video posted on social media Tuesday.

She has been in hiding since accusing Maduro of stealing last year's presidential election -- a claim backed by much of the international community.

"The long and violent abuse of power by this regime is coming to an end," she said.

Machado vowed that in a post-Maduro period, elections will be held "with security and without any manipulation."

And she said Maduro's "criminal regime must be held accountable" for its "brutality," including holding thousands of "political prisoners" behind bars.

"Venezuela will only fully rise when those who committed crimes against humanity are judged by the law and by history," said Machado.