Venezuelan authorities vowed Monday to "root out" plots against President Nicolas Maduro after what they said was a weekend drone "assassination" bid backed by Colombia.
An accusation by Maduro that his Colombian counterpart Juan Manuel Santos was behind the incident has worsened already fraught ties between Caracas and Bogota.
Santos, who hands over power to elected successor Ivan Duque on Tuesday, has categorically rejected the accusation. His government has labeled it "absurd."
A live broadcast of the incident on Venezuelan state television showed Maduro interrupted in mid-speech by an explosion and looking up in confusion.
Dozens of soldiers on parade are then seen breaking ranks and running away in panic.
Maduro and his government said the president had been targeted by two flying drones carrying explosives. But details of the incident remain unclear, with conflicting information coming from various sources.
The Maduro administration blamed the alleged attack on Colombia, working with the "ultra far-right" Venezuelan opposition, and financed by unnamed figures in the US state of Florida.
No evidence was given to support the allegations. Thousands of exiled Venezuelans live in Colombia and in Florida.
- Suspects 'identified' -
Maduro's critics said they feared the Venezuelan government would now step up repression of the opposition and dissidents.
Venezuelan Attorney General Tarek William Saab told a news conference on Monday that several suspects were in custody and authorities would track down all those who conspire against public peace."
He called the drone attack, in which seven soldiers were said to be wounded, "an attempted massacre."
"Let this act serve to root out once and for all any sort of violent attempt to threaten the peace," Saab said.
The attorney general added that two of the suspects were "caught in the act" guiding one of the drones from a car close to the parade.
He did not identify any of the suspects but said that "initial international connections have been established."
Interior Minister Nicolas Reverol said Sunday that six suspects had been arrested.
He said two drones had been used, each carrying a kilogram (2.2 pounds) of C4 explosive.
One went out of control and flew into a building, while the other was jammed and exploded before reaching the president's podium, Reverol said.
Maduro's supporters marched through Caracas on Monday.
The 55-year-old Socialist leader was expected to address them in what would be his first public appearance since Saturday's incident.
No drones could be seen in the broadcast of the event, which was cut moments after the soldiers were seen scattering away from where Maduro was standing flanked by military chiefs and his wife.
Some accounts on the ground said a fire at a nearby building was caused by the accidental explosion of a gas cylinder.
An unauthenticated statement from a rebel group calling itself the "National Movement of Soldiers in T-Shirts" claimed responsibility in a statement passed to an opposition journalist based in the US.
Maduro and his allies, however, insist it was a drone assassination bid. Bolivia, Cuba, Iran, Russia and Syria condemned the incident.
- Persecution feared -
Maduro, a 55-year-old former bus driver who took over the reins from his mentor Hugo Chavez upon the latter's death to cancer in 2013, has been ruling in increasingly autocratic fashion with military support.
He controls almost all the country's institutions, and has used the supreme court, electoral authorities and a new super-legislative body, the Constitutional Assembly, to sideline the opposition-run parliament, the National Assembly.
Although he won a new six-year term in controversial snap elections boycotted by the opposition, Maduro remains widely reviled for presiding over a collapsing economy.
Inflation this year is projected to reach as high as one million percent, according to the International Monetary Fund. Oil exports -- a vital money-earner for a country sitting atop the world's largest crude reserves -- have declined sharply.
Venezuela's currency, the bolivar, is practically worthless and food and medicine are extremely scarce, prompting hundreds of thousands of Venezuelans to flee abroad.
The country is largely isolated internationally and is subject to US sanctions that greatly degraded Caracas's capacity to raise credit.
Maduro regularly accuses the "imperialist" United States of plotting coups against him and waging "economic war" on Venezuela.
Venezuelan President Nicolas Maduro (C) attends a ceremony to celebrate the 81st anniversary of the National Guard in Caracas on August 4, 2018
Screengrab taken from a handout video released by Venezuelan Television (VTV) showing Venezuelan Maduro (C), his wife Cilia Flores (L) and military authorities reacting to a loud bang during a military parade
Outgoing Colombian President Juan Manuel Santos has categorically rejected the accusation that he was behind the drone attack against Maduro
Brief biography of Maduro