US Treasury warns foreign banks against transacting with Iran or face immediate secondary sanctions

The U.S. Department of the Treasury issued an urgent financial alert on Monday, warning foreign financial institutions that continuing to conduct business with Iran's banking sector or shadow financial networks will trigger immediate secondary sanctions without prior notification.

What specific warnings did the US Treasury issue to foreign banks?

In an official compliance alert, the Treasury's Office of Foreign Assets Control (OFAC) instructed international banks and non-bank financial intermediaries to immediately identify, freeze, and terminate all financial ties with sanctioned Iranian entities. The advisory emphasized that foreign institutions found facilitating Iranian commerce risk losing access to the U.S. dollar financial system.

"Foreign financial institutions continuing to transact with sanctioned Iranian financial institutions could be targeted at any time without advance notification and should take immediate action to terminate such activity and relationships," the Treasury statement warned. The alert specifically directed global compliance officers to scrutinize "shadow banking" channels—complex networks of front companies, exchange houses, and third-party intermediaries operated by Tehran to bypass international sanctions and move capital covertly.

How is Washington expanding its economic isolation campaign against Tehran?

The regulatory alert reflects a broader campaign by Washington to step up financial pressure alongside military actions that began in late February:

• Sector-Wide Targeting: Since late August, the U.S. administration has steadily expanded secondary sanctions, targeting key pillars of Iran's economy, including its financial, cryptocurrency, railway, automotive, and heavy manufacturing sectors.
• Enforcement Against Foreign Institutions: The warning follows recent enforcement actions against foreign financial entities, including sanctions levied on two banks located in the United Arab Emirates and Turkey for allegedly facilitating illicit Iranian financial transactions.
• Global Economic Impact: The aggressive sanctions enforcement arrives as the ongoing conflict and Iran's maritime interdictions in the Strait of Hormuz continue to disrupt global supply chains, driving up energy, transport, and agricultural fertilizer costs worldwide.

According to The Wall Street Journal and Bloomberg, international banking groups across Europe, Asia, and the Middle East are accelerating internal audits to ensure complete detachment from Iranian-linked transaction flows.