The Trump administration on Friday condemned Venezuela's President Nicolas Maduro for what it said was his reliance on foreign military personnel to stay in power and renewed a warning to Russia against getting involved.

President Donald Trump's national security adviser John Bolton along with the U.S. special envoy for Venezuela Elliott Abrams said Russia's military presence in the country is destabilizing amid the country's political and economic crisis.

"We strongly caution actors external to the western hemisphere against deploying military assets to Venezuela, or elsewhere in the hemisphere, with the intent of establishing or expanding military operations," the national security adviser said in a statement released by the White House.

His comments come amid U.S. attempts to press Maduro to give up power, arguing his re-election last year was not legitimate. The Trump administration has joined more than 50 other nations in recognizing the opposition head of the National Assembly, Juan Guaido, as interim president.

U.S. officials have in recent days stepped up their warnings to Russia about becoming involved militarily following the arrival in Caracas of Russian military planes carrying personnel and cargo.

Abrams, speaking to reporters at the State Department after Bolton's statement was released, said the U.S. estimates there are about 100 Russian military personnel in Venezuela, primarily working on the South American country's Russian-purchased S-300 air defense systems, which may have been damaged by recent widespread power outages.

Abrams also said the presence of several thousand Cubans, mainly in Venezuela's intelligence services, was troubling.

"Their presence is extremely pernicious, the same thing is true I would say of the Russian presence," he said.