Venezuelan officials reached out to the US behind President Maduro's back solely to discuss his exit from power and free elections, National Security Advisor John Bolton has said.
Mr Bolton's comment came after Nicolas Maduro said he had authorised the contacts with high level US officials, casting them as a long-standing initiative that he was aware of and had approved.
Countering in a tweet, Mr Bolton said: "The only items discussed by those who are reaching out behind Maduro's back are his departure and free and fair elections."
He noted that US President Donald Trump "has repeatedly stated, to end the pilfering of the Venezuelan people's resources and continued repression, Maduro must go."
Mr Trump told reporters at the White House yesterday that the US was in discussion with Venezuelan officials "at a very high level."
"We are in touch. We're talking to various representatives of Venezuela," he said.
President Maduro has so far survived mass street protests, a failed military uprising and international challenges to his legitimacy as the once-rich, oil-producing country spins deeper into crisis.
As the President has repeatedly stated, to end the pilfering of the Venezuelan people's resources and continued repression, Maduro must go. The only items discussed by those who are reaching out behind Maduro's back are his departure and free and fair elections.— John Bolton (@AmbJohnBolton) August 21, 2019
The Trump administration has thrown its backing behind Venezuela's National Assembly leader, Juan Guaido, as the legitimate president.
Mr Guaido, who is supported by more than 50 countries, proclaimed himself acting president in January after the opposition-controlled National Assembly declared that Maduro had usurped power through fraudulent elections last year.
In a message broadcast on radio and television yesterday, Nicolas Maduro said he had authorised the back channel talks with US officials.
"For months there has been contact between senior officials of the United States, of Donald Trump, and the Bolivarian government that I preside over," Maduro said.
"Just as I have sought dialogue in Venezuela, I have sought a way in which President Donald Trump really listens to Venezuela," he said.
Washington has been pressuring President Maduro through sanctions to step down while publicly prodding members of his inner circle to cut their ties to him before it is too late.
"We're staying out of it, but we are helping it, and it needs a lot of help," Mr Trump said of Venezuela.
"It's an incredible tribute to something bad happening, and the something bad is socialism," he said.
Among the Venezuelan officials reported to have held talks with US representatives is Diosdado Cabello, considered the second most powerful person after Maduro in the leftist regime.
Mr Cabello heads the Constituent Assembly, a body set up by the regime and given extraordinary powers superseding the National Assembly.
John Bolton has said Defense Minister Vladimir Padrino and other key leaders pledged support for Maduro's ouster in April. But they swung behind the embattled Venezuelan president after a Guaido-led military uprising fizzled on 30 April.
One key conspirator, the head of the feared Sebin intelligence services, General Manuel Cristopher Figuera, turned up in the US after fleeing the country when the uprising failed.
Norway had mediated talks between the government and the opposition on the way forward, but Maduro pulled out of those on 7 August, after the latest round of US sanctions.