Venezuelan President Nicolás Maduro says security forces have foiled a plot to assassinate him and install a former defence minister as premier.
He said the "fascist" plot had involved opposition leader Juan Guaidó backed by the US, Colombia and Chile.
Mr Guaidó denied the accusation, saying the media had "lost count" of how many such allegations had been made.
The president has intensified a crackdown on the opposition since Mr Guaidó led a failed uprising in April.
Communications Minister Jorge Rodriguez suggested the alleged coup had been brought down by informers within the group.
"We were in all the meetings to plan the coup... We were in all the conferences," he said.
According to Mr Rodriguez, more than two dozen people - including active and retired military officers - had been involved.
The plot allegedly consisted of plans to seize three key military bases and kill the president, his wife, and several top officials in the government and Socialist Party.
Mr Rodriguez said the plotters had also intended to break former Defence Minister Raul Baduel out of prison and proclaim him president.
Mr Baduel emerged as a prominent opposition leader in 2007 after serving under President Hugo Chávez. He gained international attention in 2009 when authorities jailed him for historic corruption charges, all of which he has denied.
Without referring directly to the accusation, Colombian Foreign Minister Carlos Holmes Trujillo said his country would "continue to act through political and diplomatic means" in Venezuela.
Some four million people have fled Venezuela since 2015, according to the UN, amid a severe year-long economic crisis that has resulted in high unemployment and chronic shortages of food and medicine.
Mr Guaidó, head of the country's National Assembly, declared himself interim president in January and has the backing of more than 50 countries, including the US and most of Latin America.
But Mr Maduro retains the loyalty of most of the military and important allies such as China and Russia.