The United States government will impose new sanctions on the Venezuelan Central Bank, which is the institution that is "keeping (President Nicolas) Maduro in power," US President Donald Trump's national security adviser, John Bolton, said on Wednesday in Miami.

At a luncheon with Cuban exiles belonging to the Bay of Pigs Veterans Association-Brigade 2506, Bolton said that, on behalf of the administration, he was "pleased to announce new sanctions against the Central Bank of Venezuela to restrict US transactions with this bank and prohibit its access to US dollars."

"The Central Bank of Venezuela has been crucial to keeping Maduro in power, including through its control of the transfer of gold for currency," the arch-conservative national security adviser told the Cuban exile organization.

"The United States will use its economic tools to the maximum capacity to constrict Maduro and ensure that his cronies no longer pilfer what rightfully belongs to the people of Venezuela," he added.

He warned that "These steps against Venezuela's Central Bank should be a strong warning to all external actors, including Russia, against deploying military assets to Venezuela to prop up the Maduro regime."

Bolton went on to say that many countries in the region have condemned the Russian "military flights" to Venezuela "carrying 35 tons of unknown cargo and 100 military personnel."

He added that the US "will consider such provocative actions a threat to international peace and security in the region."

Russia - a staunch ally of Maduro's beleaguered leftist government - dispatched two cargo planes filled with troops and military equipment to Venezuela last month, hiking tensions with Washington.

On March 28, Trump said that Moscow "needs to get out" of the South American country, which is mired in a severe political, economic and social crisis that has resulted in tremendous scarcities of basic products, including medicines, along with rampant hyperinflation.

US Vice President Mike Pence said that the Russian flights were "an unwelcome provocation."

Moscow, on the other hand, said that the deployment was fully in keeping with its defense cooperation with Caracas, adding that the troops will remain in Venezuela for as long as needed.

Calling Cuba, Venezuela and Nicaragua the "three stooges of socialism," Bolton told the exile organization that this "troika of tyranny ... is beginning to crumble."

He announced a new US cap of $1,000 per quarter on the amount of remittances people in the US can send to their relatives in Cuba, noting that the Barack Obama administration had lifted the limits on money that Cuban exiles and others could send to family members on the communist island.

He also announced sanctions on financial services provider Bancorp, claiming that it operated as a "slush fund" for Nicaraguan President Daniel Ortega.

"The United States looks forward to watching each corner of this sordid triangle of terror fall: in Havana, in Caracas, and in Managua," Bolton said.