President of the United States Donald Trump has imposed a ban on trading Venezuelan crypto currency "El Petro".

Namely - the ban touched all deals with digital currencies, coins tokens issued on behalf of the Venezuelan government for citizens and legal entities of the United States.
The decree is here:
https://www.whitehouse.gov/presidential-actions/executive-order-taking-additional-steps-address-situation-venezuela/

This act also provides broad powers to the US Treasury under the International Emergency Economic Empowerment Act (IEEPA) to uphold a moratorium on operations related to El Petro.

The question is, what steps can the US Treasury and FinCEN take under this decree. Indeed, IEEPA grants the executive authority not only to regulate and prohibit transactions with the "El Petro" crypto currency, but also to suspend the turnover of currencies and securities associated with "El Petro" and the economy of Venezuela.

Theoretically under the decree may fall:

• Bitcoin (MTC) and Efirium (ETN), as "El Petro" was sold for these currencies. Investing in these crypto currencies causes their growth, indirectly helping the Maduro regime. The US Treasury may try to limit the use of these crypto-currencies in cross-border payments with Venezuela.
• Platform NEM, which issued the crypto currency "El Petro". Any exchange in pairs of this NEM (XEM) crypto currency can also contribute to the development of the Venezuelan economy.

Such actions fully meet the position of the US Treasury Secretary.
Secretary of the US Treasury Stephen Mnuchin last year said that he "very carefully" looks at bitkoyn and wants to prevent its use in the shadow economy. Such actions allow the US Treasury to squeeze into the ranks of regulators of the crypto-currency markets and snatch a piece of influence in these markets.