Zakharova did not say how many Russia military experts have gone to Venezuela, but news reports indicated that two Russian planes delivered about 100 servicemen and 35 tons of cargo to Venezuela over the weekend.
"Some liken the U.S. to an elephant in a china shop, but those animals behave delicately and reasonably," Zakharova said. "It acts on the international arena more like a cowboy in the Louvre Museum."
The U.S. and several dozen other nations have cast their support behind opposition leader Juan Guaido and recognized him as interim president, asserting that Maduro's re-election last year was illegitimate.
Russia and China, which invested heavily in Venezuelan oil industries, have staunchly backed Maduro.
Speaking on Russian state television, Konstantin Kosachev, the head of the foreign affairs committee in the upper house of Russian Parliament, also defended Moscow's military cooperation with Venezuela as "fully legitimate."
He rejected the U.S. demands on Russia to end support for Venezuelan President Nicolas Maduro as "totally unacceptable" and invited the U.S. to "set a good example" by cutting its own global presence.
"A list of countries outside the Western Hemisphere where America has nothing to do will be too long," Kosachev said on Facebook. "And the withdrawal of the 'global cop' will definitely help independence and democracy in those regions much more than its constant military presence."
Nataliya Vasilyeva in Moscow contributed to this report.