The U.S. Department of the Treasury's Office of Foreign Assets Control (OFAC) has announced that certain individuals have been added to its Specially Designated Nationals and Blocked Persons List. This action means that all property and interests in property within U.S. jurisdiction belonging to these individuals are blocked. U.S. persons are generally prohibited from conducting transactions with these individuals. More details, including the list and additional information about OFAC's sanctions programs, can be found on their website.
Simple Explanation
The U.S. Treasury put some people on a special list that means Americans aren't allowed to do business with them, and anything those people own in the U.S. is frozen, kind of like when a toy gets taken away and can't be played with anymore.