Trump took the step "in light of the continued usurpation of power by Nicolas Maduro and persons affiliated with him, as well as human rights abuses," according to the order.
The Wall Street Journal said the move was the first against a Western Hemisphere government in over 30 years, and imposes restrictions on Caracas similar to those faced by North Korea, Iran, Syria and Cuba.
Asked last week if he was considering a "blockade or quarantine" of Venezuela, Trump responded: "Yes, I am."
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The order affects "all property and interests in property of the Government of Venezuela that are in the United States, that hereafter come within the United States, or that are or hereafter come within the possession or control of any United States person."
These assets "are blocked and may not be transferred, paid, exported, withdrawn, or otherwise dealt in," the order said.
The measure also bars transactions with Venezuelan authorities whose assets are blocked.
It prohibits "the making of any contribution or provision of funds, goods, or services by, to, or for the benefit of any person whose property and interests in property are blocked pursuant to this order," as well as "the receipt of any contribution or provision of funds, goods, or services from any such person."
Venezuelan opposition leader Juan Guaido, who is recognised as interim president by the US and dozens of other countries, tweeted his approval of the move, saying it "seeks to protect Venezuelans" from Maduro's "dictatorship."
"Those who support it, benefiting from the hunger and pain of Venezuelans, should know that it has consequences," Guaido said.
Guaido earlier this year declared himself interim president in a bid to oust Maduro.
But the socialist leader has refused to yield, and in the executive order Trump blamed Maduro's government for "ongoing attempts to undermine" Guaido and the opposition-controlled National Assembly, which he leads.
Guaido's efforts have meanwhile stalled despite the international support and widespread discontent with Maduro, who has been able to cling to power with the backing of the country's security forces.
The two sides began negotiating in Norway in May, with the most recent round of talks opening last week in Barbados.
Both Guaido and Maduro have "reiterated their willingness" to resolve the political crisis, mediator Norway has said, but the talks have produced no resolution yet.
The parties have in the past laid out starkly opposing positions, with Guaido and the opposition calling Maduro a "usurper" and accusing him of having rigged the 2018 poll that saw him re-elected.
They want him to stand down so new elections can be held.
Maduro has refused to resign and says the negotiations must lead to "democratic coexistence" and an end to what he describes as an attempted "coup" orchestrated by the United States.
Despite the loss of momentum, Guaido remains the greatest threat to Maduro, even though the National Assembly has been effectively rendered powerless by Caracas.
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The oil-rich, cash-poor country has been in a deep recession for five years. Shortages of food and medicine are frequent, and public services are progressively failing.
Around a quarter of Venezuela's 30 million-strong population needs aid, according to the United Nations, while 3.3 million people have left the country since the start of 2016.
The International Monetary Fund says inflation will hit a staggering one million per cent this year while the economy, already in recession for five years, will shrink by 35 per cent.
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