Restrict the visas of ICC officials, freeze their assets, seize any property owned by these individuals that is under jurisdiction of US or an ally of US. Since most of the financial transactions in the world are conducted using $USD, US Treasury hold the power to prevent many individuals or financial institutions from conducting business with these individiuals.
from HRW:
“US dollar-denominated transactions—even if they are between two non-US parties—usually require a bank under US jurisdiction to handle the transactions. Thus, any transaction that passes through them, even momentarily, would also be blocked.
The importance of the US dollar and the fear of losing access to risk-averse US banks means that most major financial institutions around the globe regularly refuse to conduct transactions with or for individuals on the SDN List. This is so even in transactions in which there is no connection to US dollars, US persons, or US jurisdiction. This broadens the reach of the sanctions far beyond blocking assets like bank accounts or property physically located in the US and can affect the ability of designated people to conduct any economic transactions at all on a global basis. In addition, the fear of potentially running afoul of this executive order’s vague and undefined prohibition on the provision of material assistance or support to sanctioned people creates additional risk.”