WASHINGTON (AP) — The Treasury Department wants U.S. banks and other financial institutions to monitor for suspected Iranian money laundering networks that use their funds to smuggle sanctioned oil through shell companies and crypto networks.

The move, which effectively deputizes the global financial system to help disrupt Iran’s sanctions-evasion infrastructure, comes as the U.S. and Iran reached another impasse over how to end their war while their ceasefire has grown increasingly shaky.

President Donald Trump on Monday said the Iran ceasefire is on “life support” after he rejected Tehran’s latest proposal to end the war.

The Trump administration is calling on banks to flag certain customers who may launder funds for Iran’s Revolutionary Guard — including newly formed companies moving unusually large amounts of money, firms that route payments through multiple intermediaries or transactions connected to Iranian crypto firms, among other indicators.

As part of the U.S. initiative to monitor Iranian oil sales, banks are being asked to watch out for oil labeled as “Malaysian blend” to disguise its Iranian origin, missing or falsified shipping documents or ship-to-ship oil transfers that obscure where cargo came from.

A Treasury Financial Crimes Enforcement Network report released Monday says oil firms linked to Iran conducted roughly $4 billion in transactions in 2024.

And dozens of shipping companies based in Iraq, the United Arab Emirates and Hong Kong — all connected to transporting sanctioned Iranian oil — processed about $707 million through U.S. accounts in 2024.

Along with a bombing campaign in Iran, the Trump administration has turned toward an economic-focused effort aimed at choking Tehran into submission, through sanctions and the threat of secondary sanctions on Iran's allies.

In April, Treasury sent a letter to financial institutions in China, Hong Kong, the UAE, and Oman threatening to levy secondary sanctions for doing business with Iran and accusing those countries of allowing Iranian illicit activities to flow through their financial institutions.