Donald Trump has imposed a freeze on all of the Venezuelan government’s assets in the United States.
The move represents a sharp escalation of a diplomatic and sanctions drive aimed at removing the country’s socialist president Nicolas Maduro.
The ban on Americans doing business with the Venezuelan government takes effect immediately.
An executive order signed by Mr Trump on Monday goes well beyond the sanctions imposed in recent months against the country’s state-run oil company PDVSA, the financial sector, and measures against dozens of Venezuelan officials.
The order, which falls short of an outright trade embargo, cited Mr Maduro’s continued “usurpation” of power and human rights abuses by those loyal to him.
It states: “All property and interests in property of the government of Venezuela that are in the United States… are blocked and may not be transferred, paid, exported, withdrawn, or otherwise dealt in.”
The measures represent the most crippling US efforts to remove Mr Maduro since the Trump administration recognised Venezuela’s opposition leader Juan Guaido as the country’s president in January
The Trump administration has been increasing pressure on Caracas in a bid to oust Mr Maduro from power, with most Western democracies and Latin American countries calling on Mr Maduro to step down.
But China and Russia continued to back the Venezuelan leader.
US national security adviser John Bolton warned the two countries against doubling down their support for him on Monday.
Mr Bolton said he would give a speech on Tuesday at a gathering of more than 50 countries in Lima, Peru, that would outline a planned US initiative to lead to a peaceful transfer of power in Venezuela.
Moscow and Beijing turned down invitations to attend
Mr Trump said on Thursday he was considering a quarantine or blockade of Venezuela, although he did not elaborate at the time on when or how such a measure would be imposed.
He is taking more dramatic action after numerous rounds of sanctions failed to turn Venezuela’s military against Mr Maduro or make significant progress in dislodging him.
US officials have long said they had other weapons in their economic arsenal.
They have privately expressed frustration that European partners and others have not taken stronger steps and that the months-long pressure campaign had not made more headway.
Venezuela’s Information Ministry did not respond immediately to a request to comment after the executive order was signed on Monday.