The Venezuelan politician fighting to depose Nicolás Maduro has accused his rival of attempting to obliterate the opposition challenge to his rule with a campaign of “state terrorism”.

Speaking to the Guardian nearly two weeks after his failed uprising against Maduro, Juan Guaidó claimed Venezuela’s strongman president was illegally targeting opposition leaders who took part.

At least 10 Guaidó allies are facing years in jail for their role in the abortive 30 April insurrection – with three seeking refuge in diplomatic compounds and one fleeing to Colombia in recent days.

The current location of Edgar Zambrano, the vice-president of Venezuela’s opposition-controlled parliament, is unknown after he was seized by intelligence agents last Wednesday.

“Today what we are seeing is terror, the sowing of terror, which is all the Maduro regime has left,” Guaidó said during an interview at his party headquarters in Caracas.

“What they are doing right now is basically state terrorism – because they are using the state apparatus to spread fear.”

Venezuela’s foreign minister, Jorge Arreaza, has rejected international criticism of his government’s clampdown, asking critics how they would respond to a similarly “foolhardy operation” to remove their leader.

Maduro and his backers describe the botched mutiny as a US-backed coup attempt that was defeated thanks to the loyalty of Venezuela’s armed forces.

But Guaidó, the 35-year-old president of Venezuela’s national assembly, claimed Maduro’s pursuit of opposition lawmakers reflected the desperation of a regime “in its final moments”.

“All that he has left, regrettably, is persecution,” Guaidó said of Maduro, who took power after Hugo Chávez’s 2013 death and was returned to office last year in elections widely denounced as a fraud.

Several key Maduro confidants were reportedly involved in the plot against him – including the defence minister and the head of the supreme court – and Guaidó said he believed Maduro was now racked with paranoia. “I think he mistrusts everyone … even the person who serves him coffee.”

He called the defection of Venezuela’s top spy – who Maduro has accused of being a CIA mole – proof of a deep split within the military and predicted: “There will be more and more [defections].”

Despite the recent upheaval, Guaidó cut a confident and carefree figure during the half-hour interview, at one point spontaneously breaking into a falsetto rendition of his campaign jingle: “Vamos bien!” (“We’re doing good!”). As the Guardian left his office, Guaidó beamed and flashed a V sign with his left hand.

But for all that outward bounce the politician’s life has been upended since he launched his campaign against Maduro in January by declaring himself Venezuela’s rightful interim president – a decision now endorsed by 54 governments, including the US and Britain.

Thickset security guards prowl the corridors of his offices with walkie talkies strapped to their hips. Guaidó’s wife and baby daughter have reportedly left Venezuela.

“There have been lots of threats,” he said, calling recent days “very complicated”.

Guaidó has yet to be detained or charged – something many attribute to Maduro’s reluctance to provoke the White House.

But several close allies have gone into hiding or fled abroad after being stripped of their parliamentary immunity and accused of crimes including treason, civil rebellion and instigating insurrection.

On Saturday, Venezuela’s El Nacional newspaper said Zambrano faced up to 30 years in prison for his role in the so-called “Operation Freedom” against Maduro.

Guaidó recalled feeling “great expectation” as he headed to Caracas’ La Carlota airfield to launch the rebellion in the early hours of 30 April. But by noon it was clear crucial support from top military and political figures had not materialised. “We needed more,” Guaidó admitted.

Despite the setback – which some view as a calamitous defeat and others a temporary hitch - Guaidó insisted the opposition was close to achieving its objective.

He hinted secret negotiations aimed at securing Maduro’s departure continued and said he would talk to any civil or military figure prepared to back his cause.

Asked how long Maduro had left, Guaidó said he hoped it was “nanoseconds”.

“They have already lost. Venezuela hasn’t won yet … [but] I believe it is just a matter of time.”

Maduro loyalists see the uprising as part of a gringo plot masterminded by Donald Trump’s White House. Pedro Carreño, a top Maduro ally, branded Guaidó’s movement a “despicable” jukebox that would play whatever tune it was paid to.

Guaidó rejected his depiction as a “diabolical imperialist puppet” and urged foreign critics to consider how Chavista criminality – not US sanctions – had caused Venezuela’s collapse.

“It wasn’t a tornado. It wasn’t a hurricane. It wasn’t an earthquake. It wasn’t a fire that spread uncontrollably,” Guaidó said. “No – it was caused by the corruption of this regime.”

Additional reporting by Patricia Torres in Caracas