Hundreds of soldiers broke ranks and sprinted for cover as blasts rang out over the capital Caracas. Seven soldiers were hurt.
The explosions cut short a televised speech by the president during the National Guard's 81 anniversary celebration.
Mr Maduro - blamed for the impoverished country's crippling inflation and shortages of basic goods - was unharmed.
Information Minister Jorge Rodriguez condemned it as an attempted attack on the President's life.
He said: "At exactly 5:41 p.m. in the afternoon several explosions were heard. The investigation clearly reveals they came from drone-like devices that carried explosives."
Related: Breitbart - Darth Bolton: ‘Wouldn't us! No US govt involvement’ in reported Venezuela attack