National Security Adviser John Bolton said President Donald Trump is working towards "the first completely free hemisphere in human history" with his Venezuela policy during an appearance on PBS NewsHour Wednesday.

Anchor Nick Schifrin asked Bolton to explain his view that the Monroe Doctrine remains in force in American foreign policy. The Monroe Doctrine is a principle of American foreign policy from the early 19th century which admonished European nations to refrain from intervening in the Western Hemisphere.

"I think many U.S. allies in this region, in this hemisphere, those closest to us, welcome the U.S. leadership here under President Trump to keep foreign powers from extending their influence, particularly in Venezuela, which is what I was referring to when I said the Monroe Doctrine is alive and well. It's intended to throw a shield around the hemisphere," Bolton said.

"It's worked for a long time, and I think it's an important doctrine to keep in mind as we work for the objective that President Trump seeks here, which is the first completely free hemisphere in human history. We're not embarrassed by that," Bolton added.

"What do you say to those people who call it imperialist?" Schifrin asked.

"You know, the United States has never been an imperialist power," Bolton said. "We're not starting now. What we want is to prevent others with imperialist aims from taking advantage of weakness, of the corruption and authoritarian nature of the Maduro-Chavez regime in Venezuela. That's what we had in mind."

Bolton would not get into specifics as to how the United States would respond to Russian intervention in Venezuela, but he reiterated that all options are on the table.

"It's for Maduro to worry about what the United States is capable of, and it's also to make it clear, we value the protection of the 40 to 45,000 American citizens in Venezuela. We don't want to see any harm come to them," Bolton said.

"The fact is, I think, with respect to Russia, China and others, they're already hedging their bets in Venezuela," Bolton added." They've done certain things that we object to, but I think they understand if they're not careful and there is a peaceful transition of power to Juan Guaidó and the opposition, that they need to watch how they behave and their actions with respect to Maduro, or their very substantial debts they've forced on the Maduro government could be in jeopardy. That's something they need to think about, I believe."

Earlier Wednesday, the U.S. announced it is imposing sanctions on the Central Bank of Venezuela.

Russia sent troops to Venezuela last month in an effort to prop up the Nicolas Maduro regime.

Venezuela's constitutional crisis emerged in the wake of disputed elections last year. Maduro was sworn in for a second term, but National Assembly president Juan Guaidó declared himself the legitimate leader of Venezuela because the country's constitution permits him to assume temporary power if the president is improperly elected.

The U.S., most of Latin America, and the European Union have thrown their support to Guaido, while Russia, China, and Cuba have sided with Maduro.