"I don't know about the presence of any Russian private military companies in Venezuela. This is another hoax," Zaemskiy said.
Earlier in the day, Reuters news agency reported, citing anonymous sources, that "private military contractors who do secret missions for Russia" had recently arrived in Venezuela, which is currently going through a political crisis, to boost safety of the country's incumbent president, Nicolas Maduro.
Kremlin spokesman Dmitry Peskov told Reuters that Kremlin had "no such information."
On Tuesday, the opposition-run Venezuelan National Assembly adopted a statement declaring President Nicolas Maduro a "dictator." On Wednesday, opposition leader Juan Guaido proclaimed himself the country's interim president at a mass rally in Caracas. The United States, Argentina, Brazil, Canada, Chile and Colombia, among others, have recognized Guaido as Venezuela's interim president, while some other countries, including Russia and Mexico, expressed support for incumbent President Maduro.