The Trump administration announced Monday it was imposing sanctions on Venezuela's state-owned oil company in an effort to ratchet up the pressure on Nicolas Maduro.

The sanctions, announced at the White House, would target the firm, called Venezuela, S.A. (PdVSA), in order to 'preserve these assets for the people of Venezuela' rather than the Maduro government.

In the U.S. it operates the Citgo chain of gas stations.

The move comes days after Trump recognized Juan Guiaido as the legitimate leader of Venezuela, a top oil exporter.

'We have continued to expose the corruption of Maduro and his cronies,' said National Security Advisor John Bolton at the White House Monday.

Trump's national security advisor John Bolton said Monday's announcement would block Maduro from accessing PDVSA assets worth $7 billion and cost him $11 billion in lost export proceeds over the next year.

The United States stopped short, however, of imposing a ban on imports of Venezuelan oil, a move that U.S. oil refiners had opposed.

Treasury Secretary Steven Mnuchin said Citgo in the United States would be able to continue to operate, provided funds go to a blocked account.

Treasury Secretary Steven Mnuchin (R) and National Security Advisor John Bolton announce the Trump administration's economic sanctions against Venezuela and the Venezuelan state owned oil company Petroleos de Venezuela (PdVSA) during a press briefing at the White House in Washington, U.S., January 28, 2019

Although oil purchases continue, any funds would be placed into blocked accounts. The administration is still working on how and when those funds could be accessed by Guiaido, Treasury Secretary Steven Mnuchin said.

'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,' Mnuchin said.

In announcing the sanctions, Bolton also repeated his warning for military forces under Maduro's control not to use force on civilian protesters.

'We have continued to expose the corruption of Maduro and his cronies,' said National Security Advisor John Bolton at the White House Monday.

The sanctions follow President Trump's decision to recognize the government of opposition leader Juan Guaido

'This is an unequivocal statement on our part,' he said. Asked about any potential military response by the U.S., Bolton repeated Trump's words that 'all options are on the table.'

The oil company's assets in the U.S. would be frozen under the sanctions.

Mnuchin noted that Venezuela is rich in oil deposits, even amid widespread food shortages under the Maduro regime. 'There's no reason for the poverty and the starvation and the humanitarian crisis,' he said.

According to a Treasury statement announcing the statements, 'As Venezuela's state owned oil company, PdVSA has long been a vehicle for corruption. A variety of schemes have been designed to embezzle billions of dollars from PdVSA for the personal gain of corrupt Venezuelan officials and businessmen.'

Bolton appealed directly to the military which has been essential to keeping Maduro in power since 2013.

'We also today call on the Venezuelan military and security forces to accept the peaceful, democratic and constitutional transfer of power,' Bolton said.

'To a certain extent, this has begun,' he said. 'We've seen Venezuelan official and military personnel heeding this call,' he added, citing the example of the country's military attache to Washington who broke ranks with Maduro at the weekend.

Asked whether Trump would consider getting the US military involved in Venezuela, Bolton replied: 'The president has made it clear on this matter that all options are on the table.'

'For example, a 2014 currency exchange scheme was designed to embezzle and launder around $600 million from PdVSA, money obtained through bribery and fraud. By May 2015, the conspiracy had allegedly doubled in amount, to $1.2 billion embezzled from PdVSA,' according to Treasury.

Trump spoke to key Senate confidant Lindsey Graham about a U.S. 'military option' in Venezuela, the South Carolina Senator revealed.

Trump asked Graham – who has taken out a hard line on the use of force in Iraq and Syria and confronting Russia – for his views weeks ago, before announcing he was recognizing opposition leader Juan Guaido amid a series of massive street protests against President Nicolas Maduro.

Graham, who has counseled Trump on the government shutdown and other matters, said Trump asked him: 'What do you think about using military force?,' Axios reported.

Sen. Lindsey Graham says President Trump asked him about a U.S. 'military option' in Venezuela

The senator urged caution as he counseled about a country and a region where U.S. military interventions have not always turned out as planned.

'Well, you need to go slow on that, that could be problematic,' Graham said he responded.

He says Trump responded with a joke, saying: 'Well, I'm surprised, you want to invade everybody.'

'And I said, 'I don't want to invade everybody, I only want to use the military when our national security interests are threatened,' Graham countered.

'We're not considering anything, but all options are on the table,' President Trump said when asked about the use of military force in Venezeula

Members of civil society arrive at the control post of the presidential residence, known as La Casona, to deliver the Amnesty Law, in Caracas, Venezuela, 27 January 2019. The Venezuelan opposition began a campaign to get the military and police of the country the text of a law recently approved by Parliament, where it exercises a strong majority, and seeks officials to ignore the Government of Nicolas Maduro

A handout photo made available by the Miraflores Press, shows Venezuelan President Nicolas Maduro (C) as he leads a military exercise, in Caracas, Venezuela, 27 January 2019. Maduro led on Sunday military maneuvers with soldiers, as the opposition went to barracks to deliver to the uniformed of the country the text of a law with which they seek to get them to disown the president.

Handout picture released by the Venezuelan presidency showing Venezuela's President Nicolas Maduro (R) speaking to troops during military exercises at Fort Paramacay in Naguanagua, Carabobo State, Venezuela, on January 27, 2019

Venezuela's President Nicolas Maduro speaks with Venezuela's Defense Minister Vladimir Padrino Lopez and Remigio Ceballos Strategic Operational Commander of the Bolivarian National Armed Forces, during a military exercise in Valencia, Venezuela January 27, 2019

Trump last week announced that the U.S. would recognize Guaido as the legitimate president of the country.

He said he 'will continue to use the full weight of United States economic and diplomatic power to press for the restoration of Venezuelan democracy.' He said the U.S. would 'continue to hold the illegitimate Maduro regime directly responsible for any threats it may pose to the safety of the Venezuelan people.'

Trump refused to rule out military action when asked about it following his announcement.

'We're not considering anything, but all options are on the table,' Trump said.

Secretary of State Mike Pompeo kept up the tough rhetoric at the United Nations, telling other nations: 'Either you stand with the forces of freedom, or you're in league with Maduro and his ­mayhem.'

Regime ally Russia has accused the U.S. of trying to stage a coup, and according to a report last week has dispatched about 400 military contractors to help Maduro with security amid street protests that have resulted in multiple deaths amid a military crackdown.