Venezuela's Supreme Court meanwhile slapped an asset freeze and travel ban Wednesday on Attorney General Luisa Ortega
Venezuela's leader Nicolas Maduro vowed Wednesday to fend off what he called a coup attempt after a rogue cop allegedly dropped grenades from a helicopter in an attack the opposition and analysts said could be a hoax.
The socialist president put the military on alert after the attack, a potentially dramatic escalation of the violence gripping the oil-rich South American country.
He blamed the attack on Oscar Perez, a police pilot-turned-actor who appeared in a video online claiming that he and other officers were launching an "aerial deployment" to push Maduro to quit.
Beyond his police work, Perez has acted in a Venezuelan action film, "Suspended Death," and has posted photographs on social media of himself posing with weapons.
"We are a coalition of military, police and civilian public servants... opposed to this transitional, criminal government," said Perez, flanked by four masked figures in black, two of them holding rifles.
Army on alert
Maduro has for months been fending off calls for elections to replace him, from opponents who blame him for a desperate economic crisis that has sparked hunger and deadly violence.
He so far retains the public backing of the military high command -- a factor that analysts say is decisive if he is to remain in power.
Venezuela has seen three attempted military coups since 1992.
Maduro said no one was hurt in the helicopter attack, but branded it a "terrorist attack," part of an "escalation" by right-wing "coup" plotters.
"I have activated the entire armed forces to defend the peace," he said in remarks broadcast from the presidential palace.
Vice-President Tareck El-Aissami said later that the helicopter used in the attack had been found in Osma, a town near Caracas. No arrests had been made, he added.
Photos circulating on social media showed a helicopter flying over Caracas as explosions were heard.
In the video published by Venezuelan media, Perez called on Maduro to resign and for early elections to be held.
Maduro said Perez had served as pilot for former interior minister Miguel Rodriguez Torres, a retired general who has since fallen out with the president.
Hoax or real?
Leaders of the opposition MUD coalition said there was not yet enough information to comment.
"Some people say it is a hoax, some say it is real, some say that it was police personnel who really are fed up," opposition legislative speaker Julio Borges told reporters.
"Whatever it is, it is very serious. It all points to one conclusion: that the situation in Venezuela is unsustainable."
Defense affairs specialist Rocio San Miguel said it was unlikely that "a military uprising is occurring."
Maduro last week said he had replaced the heads of the army, navy, central strategic command and the military police.
"It is possible that the helicopter incident was organized by the government, whether to distract attention... or provoke a reaction from the middle ranks in order to continue purging the security forces," said Venezuelan analyst Diego Moya-Ocampos of London-based economic research group IHS Markit.
US plot alleged
Venezuela's Supreme Court meanwhile slapped an asset freeze and travel ban Wednesday on Attorney General Luisa Ortega, a top critic of Maduro, after she accused him of creating a climate of terror.
The court, which is closely aligned with the embattled president, set a hearing for July 4 to decide whether Ortega should face trial for alleged professional malpractice -- charges she has branded a political witch-hunt.
Maduro on Tuesday announced the arrests of five opponents he accused of plotting against him to clear the way for a US invasion.
Maduro's Foreign Minister Samuel Moncada complained that many countries were staying "silent" about the alleged coup plot.
"They are protecting the authors of this deed by their complicity and feigned ignorance," he told a news conference on Wednesday.
The international community has called for mediation to solve the Venezuela crisis after Vatican-backed talks last year broke down.
European Union spokeswoman Catherine Ray said Tuesday's events showed "the tensions and violence seem to have gone a step further" in Venezuela.
"We expect all parties to urgently put an end to violence and avoid the use of force," she said.