Caracas fears the deployment, which also includes F-35 stealth warplanes sent to Puerto Rico and six US Navy ships in the Caribbean, is a regime-change plot in disguise.
President Nicolas Maduro, whose last two re-elections were dismissed as fraudulent by Washington and dozens of other countries, has accused the Trump Administration of “fabricating a war”.
On November 2, Trump played down the prospect of going to war with Venezuela but said the days of Maduro - whom he accuses of being a drug lord - were numbered.
US forces have carried out strikes on about 20 vessels in international waters in the region since early September, killing at least 76 people, according to US figures.
The Trump Administration says the US is engaged in “armed conflict” with Latin American drug cartels, which it describes as “terrorist” groups.
Washington has not provided any evidence to show the stricken vessels were used to smuggle drugs, and human rights experts say the attacks amount to extrajudicial killings even if they target known traffickers.
‘Unacceptable’
Venezuela announced what it called a major, nationwide military deployment to counter the US naval presence off its coast.
The Defence Ministry in Caracas spoke in a statement of a “massive deployment” of land, sea, air, river and missile forces as well as civilian militia to counter “imperial threats”.
Defence Minister Vladimir Padrino said 200,000 troops participated in an exercise, though no military activity was observed in the capital Caracas.
Padrino sought to assure Venezuelans the country was “safeguarded, protected, defended”.
“They are murdering defenceless people, whether or not they are drug-traffickers, executing them without due process,” the minister added of the US operation.
Experts have told AFP that Venezuela, with an ill-disciplined fighting force and outdated arsenal, would be at a serious disadvantage in a military standoff with the US.
Russia denounced US strikes on boats from Venezuela - an ally of Moscow - as “unacceptable”.
“This is how, in general, lawless countries act, as well as those who consider themselves above the law,” Foreign Minister Sergei Lavrov said in televised remarks, questioning what he described as a “pretext of fighting drugs”.
Maduro relies heavily on the Kremlin for political and economic support.
US-Russia relations have soured in recent weeks as Trump has voiced frustration with Moscow over the lack of a resolution to the Ukraine war.
-Agence France-Presse