President Nicolás Maduro says the Venezuelan authorities have arrested 13 people, including two US citizens whom he described as mercenaries.
The announcement came a day after Venezuelan security forces claimed to have foiled what they described as an incursion by men in speedboats from Colombia.
Officials in Washington denied any US government involvement.
Mr Maduro has often accused the US of trying to overthrow him.
Venezuelan authorities said eight armed men were killed during Sunday’s alleged coup attempt.
In a live broadcast on Monday, Mr Maduro displayed what he said were the passports of the two arrested Americans – Airan Berry and Luke Denman – who work for a Florida-based security company.
He told viewers: “They were playing Rambo, they were playing hero.”
The Venezuelan government said the group of “terrorist mercenaries” left Colombia and landed in the town of Macuto, about 21 miles (34km) north of the capital Caracas, on Sunday, before they were intercepted and arrests were made.
Jordan Goudreau, a former member of the US Army special forces who leads a Florida-based private security firm called Silvercorp USA, has since told Reuters news agency he was one of the plot’s organisers.
When he was asked about the Americans’ arrest, he said: “They’re working with me. Those are my guys.”
According to a recent investigation by the Associated Press news agency, Mr Goudreau had previously plotted cross-border incursions which had failed to get off the ground. It said he was working alongside retired Venezuelan military men, who have allegedly been training deserters from Venezuela’s security forces at secret camps in Colombia.
AP said it had found no evidence of US government involvement.
The news agency says Mr Goudreau turned his focus to Venezuela in February 2019, after he worked on security at a benefit concert on the Colombian-Venezuelan border arranged by UK billionaire Richard Branson and supported by Venezuelan opposition leader Juan Guaidó.
Mr Goudreau has also repeatedly made claims about past associations with Mr Guaidó, who is recognised by more than 50 countries as Venezuela’s legitimate leader.
On Monday, Mr Guaidó denied having anything to do with the ex-Green Beret. In a statement, he said he had “no relationship nor responsibility for any actions” taken by the US war veteran.
He also accused President Maduro’s administration of trying to distract people from recent outbreaks of violence – including a deadly prison riot on Friday and a gang battle in Caracas on Saturday night.
Mr Guaidó has the backing of Washington, which has vowed to use tough sanctions to force President Maduro and the Socialist Party out of office.