President Nicolas Maduro stands at attention during a event marking the 81st anniversary of the National Guard, in Caracas, Venezuela, on Saturday before the explosions.
Attackers are believed to have used two DJI M600 drones that each carried 1 kilogram of C-4 explosive. But the drones malfunctioned, he added - one hitting a nearby apartment building, the other crashing after getting disoriented by government jamming signals.
The government of President Nicolas Maduro stopped publishing economic indicators almost three years ago as Venezuela's socialist economic system started falling apart, making opposition legislators the only source of such figures.
Video of the scene shows Maduro speaking, followed by two explosions.
The Venezuelan president said several people involved in the attempted murder had been detained.
We'll have more on Venezuela later in the broadcast.
The Associated Press reported that the six individuals are suspected of packing two drones with explosives, which exploded during a speech Maduro was giving at a military ceremony on Saturday. Bolton said United States officials would be willing to look at any "hard information" involving the attack.
An opposition group known as Broad Front issued a statement late on Saturday warning that Maduro may use the alleged attack to clamp down further on opposition leaders and "repress the constitutional rights of the people to continue protesting for the defence of their rights".
A mysterious rebel group also claimed responsibility for the alleged attack.
Meanwhile the Colombian government has put the blame at the door of "the ultra-right wing" - its term for the opposition.
Colombia's President Juan Manuel Santos has scoffed at the accusations, saying he was fully focused on his granddaughter's baptism on Saturday, while US national security adviser John Bolton said Washington was not involved in the blast.
"This was an attempt to kill me", he said.
The self-described "son" of Chavez, Maduro says he is battling an "imperialist" plot to destroy socialism and take over Venezuela´s oil.
US President Donald Trump has been harshly critical of Maduro's leftist regime, saying it has "destroyed a prosperous nation by imposing a failed ideology".
In a statement, the Russian Federation foreign ministry said: "We are convinced that settling political differences must be carried out exclusively in a peaceful and democratic way".
Moscow sided with Maduro's regime after his government faced global isolation when close to 130 people were killed in anti-regime protests past year. Venezuelans have struggled to buy scarce food and medicine in the country amid soaring inflation rates.
Venezuelan cartoonist EDO published a drawing showing terrified soldiers fleeing under the tagline "Run Forrest, the Empire is invading us!", in allusion to the film "Forrest Gump" where Tom Hanks' character jogs across the United States.
He says the economic malaise gripping Venezuela is an "economic war" and any unrest is plotted by foreign powers.
Both drones did explode, and while Maduro escaped unscathed, the attack injured seven soldiers, according to Venezuelan authorities.