Venezuela’s opposition figurehead, Juan Guaidó, has vowed to continue fighting Nicolás Maduro’s “cowardly, miserable and murderous” regime after he was stripped of his parliamentary immunity – a move that potentially opens the door to Guaidó’s arrest.

More than 50 countries have recognized Guaidó as Venezuela’s legitimate leader since he launched his campaign to force Maduro from office in late January, including the United States, Britain and most Latin American governments.

But recent weeks have seen a growing crackdown from Maduro’s beleaguered administration, beginning with the arrest of Guaidó’s chief of staff, who has been accused of leading a terrorist cell that had plotted a wave of political assassinations.

That crackdown escalated dramatically on Tuesday evening as Maduro’s all-powerful constituent assembly voted to strip Guaidó of the legal protections he enjoys as a member of Venezuela’s opposition-controlled parliament.

“The time for justice is coming,” said Tania Díaz, the assembly’s vice president.

As the move to strip Guaidó of his immunity was confirmed, members of the Chavista assembly took to their feet and shouted: “This is justice! Popular justice!”

Guaidó hit back, branding the move a “cowardly” attempt to stifle a popular uprising against a dictatorial government incapable of providing water, electricity and jobs to its people.

Venezuela has been rocked by weeks of crippling nationwide power cuts that Maduro blames on imperialist saboteurs in league with Guaidó but most experts believe are the result of incompetence and corruption.

“They think that by attacking me and attacking those around me … they will halt the hope of change in Venzeuela,” Guaidó told reporters outside his home in the capital, Caracas. “[But] the transition is underway … nothing will stop us.”

Guaidó urged supporters to respond to Maduro’s “brute force” with intelligence, audacity, hope and more street protests and said Venezuela’s armed forces now had a decision to make about how they responded to Maduro’s move.

He said he had already spoken to “a dozen” foreign ministers and leaders about the development.

“It won’t be with violence or intimidation that they stop us,” Guaidó insisted. “If we weren’t so close [to removing Maduro], the regime wouldn’t be so desperate.”

Since launching his campaign to unseat Maduro in January, Guaidó has been open about the potential dangers. “Doing politics in Venezuela is a risk and you can pay with your life,” he told the Guardian in February. “Obviously, there is a latent risk.”

But whether Maduro’s administration will decide to follow through with Guaidó’s arrest remains unclear. Donald Trump has thrown his weight behind Guaidó and the United States has repeatedly warned that any move to imprison or harm him would be met with a “significant” response.

On Tuesday night the Republican senator Rick Scott tweeted: “I will say this again: the US will not stand idly by if anything happens to @ jguaido or his family. @ NicolasMaduro you are on notice!”

Eric Farnsworth, a former US diplomat and vice-president of the Council of the Americas, tweeted: “The US has clearly said that harming @jguaido or his family would bring a strong response … This is a red line for Maduro.”

In an interview with the Guardian last week, another prominent opposition leader, Henrique Capriles, called on Maduro and his inner circle to step down before they destroyed both their party and their country.

“They don’t care if Venezuela becomes a cemetery as long as they can carry on in [the presidential palace] Miraflores,” warned Capriles, who backs Guaidó.

“What we are living through in Venezuela is a horror film … It has turned Venezuelans into zombies,” Capriles added.

“How much longer can this last? I don’t know. Honestly, I do not know.”