April 29 (UPI) -- The United States has sanctioned 35 entities and individuals accused of overseeing a shadow-banking network that moved tens of billions of dollars for Iran, as the Trump administration flexes Washington's financial might amid a stalemate in peace negotiations with Tehran.

The sanctions announced Tuesday come as U.S.-Iran peace negotiations came to a halt last week after Tehran said it would not participate in talks until the United States lifted its blockade of sea-based trade to the Middle Eastern nation.

Those blacklisted by the Treasury include several private companies known as rahbars, which manage thousands of overseas companies used by Iranian banks cut off from the international financial system to execute payments for Iranian trade.

According to the Treasury, these rahbar companies coordinate with Iranian exchange houses and front companies to conduct international trade on behalf of the Islamic Revolutionary Guard Corps, Iran's Armed Forces General Staff, the National Iranian Oil Company and other sanctioned entities.

"By dismantling these financial channels, we advance the administration's policy in the conflict with Iran and underscore our commitment to imposing maximum pressure on Iran," State Department spokesman Thomas Pigott said in a statement.