Venezuelan government cracks down on opponents of President Nicolas Maduro over alleged armed revolt.
The arrests raised tension in the volatile South American country after Maduro launched an "anti-coup commando squad" led by his new hardline vice-president, Tareck El Aissami.
That was a response to opposition lawmakers' latest efforts to remove Maduro over an economic crisis that has caused food shortages and deadly riots.
The son of Raul Baduel, a retired general turned critic of Maduro, said on Twitter that authorities had revoked the parole of his father who served six years in jail for corruption.
Authorities also arrested opposition lawmaker Gilber Caro and two opposition councilors, Jorge Luis Gonzalez and Rosmer Rubio.
Maduro's Interior Minister, Nestor Reverol said the four were suspected of links to "a terrorist plan of destabilization."
He alleged that Caro, Gonzalez and Rubio were found in possession of firearms and explosives and that Baduel had held meetings about the plot.
Reverol also alleged the involvement of Lilian Tintori, a high-profile critic of Maduro who is the wife of jailed opposition leader, Leopoldo Lopez. Tintori earlier branded Caro's detention an "abduction."
Maduro said last week he had appointed El Aissami to crack down on "right-wing terrorists" -- his name for political opponents who he says are mounting a "coup" against him.
"The only tool the government has against the people is to use fear and terror," opposition congressional speaker Julio Borges told reporters after the latest arrests.
"That is why it has sworn in a group it calls the anti-coup squad."
The opposition MUD coalition says there are about 100 political prisoners being held in Venezuela.
It blames Maduro for an economic crisis that has prompted deadly riots and looting due to shortages of food and medicine.
It wants a popular vote on removing him from office and has called for fresh street protests on January 23.
Maduro says the crisis is the result of a US-backed capitalist conspiracy.
Opposition majority lawmakers in the National Assembly on Monday passed a motion declaring that Maduro had effectively "abandoned his post" by failing to tackle the economic crisis.
Maduro branded that move a "coup" attempt and vowed that his opponents "will have to live with the consequences."
"There is no limit to the National Assembly's abuse of power and its capacity to act ridiculously. It is self-destructing," Maduro said in televised comments.
Vatican-mediated talks between the two sides broke down last month, with the opposition accusing the government of bad faith.
Political analyst Manuel Malaver said the arrests marked "an episode of maximum tension" in Venezuela's political standoff.
"The situation is extremely dangerous and I see no will by either side to sit down and come to an agreement," Malaver told AFP.
"We are seeing the situation escalate towards a greater confrontation."