President Nicolas Maduro is blaming far-right factions in Venezuela for what he is describing as an assassination attempt.

The government says drones loaded with explosives detonated close to a military event where the Venezuelan President was giving a speech today, but he and top government officials alongside him escaped unharmed.

In an address to the nation after the event, Maduro said: "This was an attempt to kill me. Today they attempted to assassinate me."

President Maduro was giving a speech when the attack happened. Image: AAP (AAP)

He said evidence gathered thus far "points to the far right" working in conjunction with Colombians in the neighbouring Andean nation.

Maduro said he believed Colombian President Juan Manuel Santos was also responsible.

He added police had made arrests in the incident but did not immediately provide any further details.

Colombians officials have not yet commented on the accusation. Santos has become one of Maduro's most outspoken critics.

Earlier a previously unknown group claimed responsibility for the attack.

The people on stage looked up, startled as the explosion was heard. Image: AAP (AAP)

Soldiers in T-shirts said in a tweet that they 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.

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.

President Maduro was not harmed during the explosive attack. Image: AAP (AAP)

Information Minister Jorge Rodriguez characterised the incident as an attack aimed at the embattled president, who was recently elected to a new term in office despite a crippling economic and humanitarian crisis.

Maduro, a 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.