Treasury Secretary Steven Mnuchin and National Security Adviser John Bolton joined White House Press Secretary Sarah Huckabee Sanders during a press conference on Monday to announce the new sanctions, which they said had been kept secret prior to the announcement.

In making the sanctions public, the White House warned "all options are on the table" when it comes to dealing with the ongoing conflict in Venezuela.

The sanctions target Venezuela’s state-owned oil monopoly, with the US’ goal being the seizure and diverting of Mr Maduro’s wealth assets to Juan Guaido, the opposition leader who Donald Trump and other world leaders have thrown their support behind.

As the head of the country’s elected Congress, Mr Guaido invoked powers within the Constitution and declared himself the interim president of Venezuela last week.

Venezuela protests: thousands rally against government Show all 18 1 /18 Venezuela protests: thousands rally against government Venezuela protests: thousands rally against government Protesters clash with the Bolivarian National Police during a demonstration against the government of the Venezuela and president Nicolas Maduro in Caracas on 23 January 2019 EPA Venezuela protests: thousands rally against government Demonstrators cheer as Venezuela's National Assembly head Juan Guaido declares himself the country's "acting president" at a rally in Caracas AFP/Getty Images Venezuela protests: thousands rally against government Opposition supporters take part in a rally against Venezuelan President Nicolas Maduro's government REUTERS Venezuela protests: thousands rally against government Opposition supporters take part in a rally against Venezuelan President Nicolas Maduro's government in Caracas REUTERS Venezuela protests: thousands rally against government Juan Guaido, head of Venezuela's opposition-run congress, declares himself interim president of the nation until elections can be held during a rally in Caracas demanding leader Nicolas Maduro's resignation AP Venezuela protests: thousands rally against government Opposition supporters carry letters to form the word "Democracy" while taking part in a rally against Venezuelan President Nicolas Maduro's government REUTERS Venezuela protests: thousands rally against government Police watch over marching anti-government protesters in Caracas EPA Venezuela protests: thousands rally against government A vehicle is overturned as opposition demonstrators block a road during a protest against the Venezuelan government AFP/Getty Images Venezuela protests: thousands rally against government A National Police officer fires rubber bullets during a protest against Venezuelan President Nicolas Maduro's government in Caracas REUTERS Venezuela protests: thousands rally against government A demonstrator throws back a gas canister while clashing with security forces during a rally against Venezuelan President Nicolas Maduro's government in Caracas REUTERS Venezuela protests: thousands rally against government Security forces look on after clashing with opposition supporters participating in a rally against Venezuelan president Nicolas Maduro's government REUTERS Venezuela protests: thousands rally against government Demonstrators during a protest against the government of Nicolas Maduro at Plaza Altamira in Caracas Getty Images Venezuela protests: thousands rally against government Demonstrators during a protest against the government of Nicolas Maduro at Plaza Altamira in Caracas Getty Images Venezuela protests: thousands rally against government epa07313731 Opponents of Chavism demonstrate against the Government of President Nicolas Maduro in Caracas, Venezuela, 23 January 2019. Chavists and opponents are again demonstrating in the streets of the country to support or question the legitimacy of the head of state, which the Parliament and a large part of the international community do not recognize. EPA/CRISTIAN HERNANDEZ CRISTIAN HERNANDEZ EPA Venezuela protests: thousands rally against government Riot police clash with opposition demonstrators during a protest against the government of President Nicolas Maduro on the anniversary of the 1958 uprising that overthrew the military dictatorship, in Caracas on January 23, 2019. - Venezuela's National Assembly head Juan Guaido declared himself the country's "acting president" on Wednesday during a mass opposition rally against leader Nicolas Maduro. (Photo by YURI CORTEZ / AFP)YURI CORTEZ/AFP/Getty Images YURI CORTEZ AFP/Getty Images Venezuela protests: thousands rally against government The remains of a statue of Venezuela's late President Hugo Chavez is seen hanging from a pedestrian bridge after it was destroyed in San Felix, Venezuela REUTERS Venezuela protests: thousands rally against government Riot police on motorcycles clash with opposition demonstrators during protests in Caracas AFP/Getty Images Venezuela protests: thousands rally against government Supporters celebrate Juan Guaido declaration that he is Venezuelan president EPA

“We have continued to expose the corruption of Maduro and his cronies and today’s action ensures they can no longer loot the assets of the Venezuelan people,” Mr Bolton told reporters at a briefing on Monday.

The sanctions will include a freeze on any assets the firm may have in US jurisdictions and bar Americans from doing business with it.

“The United States is holding accountable those responsible for Venezuela's tragic decline, and will continue to use the full suite of its diplomatic and economic tools to support Interim President Juan Guaido, the National Assembly, and the Venezuelan people's efforts to restore their democracy,” Mr Mnuchin said on Monday.

“Today's designation of PDVSA will help prevent further diverting of Venezuela's assets by Maduro and preserve these assets for the people of Venezuela. The path to sanctions relief for PDVSA is through the expeditious transfer of control to the Interim President or a subsequent, democratically elected government,” he said.

PDSVA is the acronym for the state-owned oil company.

Senator Marco Rubio, a vocal critic of Mr Maduro who has called for such sanctions, welcomed the move even before it was announced.

“The Maduro crime family has used PDVSA to buy and keep the support of many military leaders,” Rubio said. “The oil belongs to the Venezuelan people, and therefore the money PDVSA earns from its export will now be returned to the people through their legitimate constitutional government.”

The sanctions will not likely affect consumer prices at the gas pump but will hit oil refiners, particularly those on the US Gulf Coast.

Venezuelan oil exports to the US have declined steadily over the years, falling particularly sharply over the past decade as its production plummeted amid its long economic and political crisis.

Still, Venezuela has consistently been the third- or fourth-largest supplier of crude oil to the United States, and any disruption of imports could be costly for refiners. In 2017, the most recent year that data were available, Venezuela accounted for about 6 percent of US crude imports.

Valero and Citgo are among the largest importers of Venezuelan crude.

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But Venezuela is very reliant on the US for its oil revenue. The country sends 41 percent of its oil exports to the US Critically, U.S. refiners are among the few customers that pay cash to Venezuela for its oil. That's because Venezuela's oil shipments to China and Russia are usually taken as repayment for billions of dollars in debts.