Drones loaded with explosives have detonated close to a military event in Caracas where Venezuelan President Nicolas Maduro was giving a speech.
The president and the rest of the government escaped the alleged assassination attempt unharmed in what Information Minister Jorge Rodriguez said was an "attack" against the leftist leader on Saturday.
In an impassioned address to the nation, Maduro said some of the "material authors" of an attack with explosive laded drones are now in custody.
He said far-right wing factions within Venezuela working in collaboration with conspirators in Colombia and the US were responsible.
He did not provide the names of those detained or describe the charges they are facing.
Information Minister Jorge Rodriguez said that several drones armed with explosives detonated near Maduro as he was delivering a televised speech during a military parade in Caracas on Saturday.
Maduro said he hoped US President Donald Trump was "willing to fight the terrorist groups."
Security forces check a building after an explosion was heard while Venezuelan President Nicolas Maduro was attending a ceremony. Source: AFP
He promised a full investigation to hold all those responsible, "No matter who falls."
"This was an attempt to kill me. Today they attempted to assassinate me."
Colombian President Juan Manuel Santos is one of Maduro's most outspoken critics.
Earlier a previously unknown group claimed responsibility for the attack.
Soldiers in T-shirts said in a tweet that it planned to fly two drones loaded with explosives at the president, but government soldiers shot them down before reaching its target.
The Associated Press could not independently verify the authenticity of message.
Alternative account of incident emerges
Meanwhile firefighters at the scene are disputing the government's version of events.
Three officials who spoke on condition of anonymity said the incident was actually a gas tank explosion inside an apartment.
Smoke could be seen coming out of a building window at the site of the incident.
Maduro was recently elected to a new term in office despite a crippling economic and humanitarian crisis.
The former bus driver who replaced former President Hugo Chavez after his death in 2013, won a new six-year term in May but his main rivals disavowed the election and alleged massive irregularities.
Venezuela is suffering under the fifth year of a severe economic crisis that has sparked malnutrition, hyperinflation and mass emigration.
OPEC member Venezuela's once-thriving socialist economy has collapsed since the 2014 fall of oil prices.
Incident comes during events marking anniversary
The parade Mr Maduro attended was to mark the one-year anniversary of the Constitutional Assembly, a rival legislative body packed with Maduro loyalists that arrogated powers from the opposition-ruled National Assembly.
Venezuelan President Nicolas Maduro has survived an assassination attempt at a parade in Caracas. Source: AP
Mr Maduro has remained in power over Venezuela, a major oil exporting nation, despite a collapsing economy and a long-running political crisis that has seen his country isolated internationally.
Hundreds of thousands of Venezuelans have fled the country, where food and medicine are in very short supply, and where inflation this year could reach as high as one million percent according to the International Monetary Fund.
Mr Maduro, a 55-year-old Socialist leader who took over from his late mentor Hugo Chavez in 2013, has effectively sidelined the fractured opposition through control of the courts and the electoral body - and support from the military, which holds key posts in his government.
He often accuses the opposition and the United States of working together to foment a "coup" to topple him, saying the economic malaise gripping Venezuela is an "economic war" and any unrest is plotted by foreign powers.
Troops deploy following the blast. Source: AP
A year ago, four months of street protests flared against his authority that were put down by robust action from the army, the National Guard and police, resulting in 125 people killed.
One of the key reasons for the protests was the creation of the Constitutional Assembly, which aimed to short-circuit the National Assembly in which the opposition won a supermajority in 2015 elections.
Last year, the president said the new body replaced the elected legislature.
The Supreme Court declared the National Assembly dissolved. Although it continues to operate, its decisions are routinely annulled.
The United States and other countries have expressed alarm at the loyalist structure propping up Mr Maduro, saying Venezuelan democracy was being undermined.
Mr Maduro this year brought forward presidential elections that - after they were boycotted by the opposition and key opposition figures were declared ineligible to run - handed him a new six-year term.
