A helicopter dropped two grenades on Venezuela's Supreme Court building in a "terror attack" against his government, President Nicolas Maduro said in a speech Tuesday, adding that the weapons failed to explode.
"I have activated the entire armed forces to defend the peace," he said in remarks delivered from the Miraflores presidential palace.
Maduro said he has put the military on alert to respond to the alleged assault.
"Sooner or later, we are going to capture that helicopter and those that carried out this terror attack," he declared.
He did not say when the alleged attack is supposed to have occurred, and said no one was injured and that the grenades failed to detonate.
In his speech, Maduro, 54, said that in addition to firing on Venezuela's high court, the helicopter flew over the Justice and Interior Ministeries.
The beleaguered president, who for weeks has been thundering about alleged coup plots against him, said the aircraft was flown by a pilot who worked for his former Interior and Justice minister Miguel Rodriguez Torres, from whom he is now estranged.
Earlier Tuesday, Maduro repeated claims of a US-backed coup attempt and angrily warned President Donald Trump that Venezuela would fight back against such a move.
His comments came a day after he announced the arrests of five opponents he accused of plotting against him to clear the way for a US invasion.
It was one of the more dramatic in a regular series of anti-US tirades by the socialist leader, who is resisting opposition calls for elections to remove him.
"If Venezuela were dragged into chaos and violence... we would fight," Maduro bellowed in a speech to supporters.
If a coup prevented his side fulfilling his contested reform plans, he said, "we would achieve it by arms."
He said that an armed intervention in his country would spark a crisis that would dwarf those caused by conflicts in the Middle East.
Addressing Trump, he said: "You are responsible for restraining the madness of the Venezuelan right-wing."
Maduro has a number of times claimed that the United States is to blame for the grave political and economic crisis in the oil-producing country, which has fueled the often violent demonstrations of recent months.
Clashes in anti-Maduro protests over the past three months have left 76 people dead, prosecutors say.
The opposition blames Maduro for an economic crisis that has caused shortages of food and medicine in the oil-rich country.
They regularly accuse him of repressing and jailing opponents. Judicial NGO Foro Penal says there are 383 political prisoners in Venezuela.
Addressing a crowd over the weekend, Maduro had said detainees would face military trial over an alleged coup plot, backed by Venezuelan opposition leaders and aimed at precipitating a US intervention in the country.
"I am not exaggerating when I say it would have involved the arrival of American ships and troops in Venezuelan waters, on Venezuelan soil," Maduro said.
And on Saturday the head of the Organization of American States dug his heels in a war of words with Caracas, flatly rejecting its demand that he resign.
Maduro had suggested that Luis Almagro -- who has criticized the Venezuelan government of violating human rights, interfering in elections and detaining political prisoners -- step down in exchange for the country's continued membership in the regional body.
Though Almagro dismissed that notion, the OAS General Assembly was unable to reach agreement on a plan to deal with the instability in Venezuela at a meeting in Cancun last week.