The White House imposed "tough" new sanctions against Venezuela on Thursday, denouncing Caracas as being part of a "troika of tyranny" that also includes Cuba and Nicaragua.

National Security Advisor John Bolton told an audience in Miami the sanctions would particularly target Venezuela's gold sector, which "has been used as a bastion to finance illicit activities, to fill its coffers and to support criminal groups."

"The troika of tyranny in this hemisphere — Cuba, Venezuela and Nicaragua — has finally met its match," he added, according to prepared remarks.

Bolton said the new sanctions came in the form of an executive order signed by President Donald Trump.

He also announced that the State Department has added new sanctions on more than two dozen entities owned or controlled by the Cuban military and intelligence services.

He called the leaders of Venezuela and Nicaragua "desperate" autocrats who had joined Cuban counterparts in the "same oppressive behavior of unjust imprisonment, torture and murder."

"The troika of tyranny in this hemisphere will not endure forever," Bolton said.

"Like all oppressive regimes and ideologies, it too will meet its demise."

In addressing Nicaragua, Bolton said the regime of President Daniel Ortega had "completely eroded" democratic institutions, stifled free speech and imposed a deadly policy against political opponents.

Until free, fair and early elections are held, "the Nicaraguan regime, like Venezuela and Cuba, will feel the full weight of America’s robust sanctions regime," Bolton said.