The US Treasury Department placed sanctions on 26 individuals and “entities”, which Washington said has shipped approximately $500 million worth of Iranian oil in the last year, The New York Times reported.
The sanctions freeze any assets held in the United States of those affiliated with the shipping network and prohibit them from doing business with Americans.
The action also identifies 11 ships, placing anyone who owns or operates them on a Treasury list and exposing any port that lets them in, or firms that fuel or offload them, to future sanctions.
The sanctions were the latest in a flurry of actions taken by the United States in recent days to further isolate Iran in hopes that it will return to the bargaining table to renegotiate an international agreement over its nuclear program.
Trump withdrew from the 2015 agreement in May 2018 and reinstated sanctions to limit Iranian oil sales, raising tensions with countries in Europe and Asia that have become reliant on Iran for energy.