Bangladesh, July 3 -- In a bold escalation of its efforts to combat the synthetic opioid crisis, the US Treasury Department has announced sweeping sanctions against three Mexican financial institutions accused of laundering money for drug cartels deeply involved in fentanyl trafficking. The action, unveiled on June 25, marks the first use of powers granted under the recently enacted FEND Off Fentanyl Act, signaling Washingtons intent to wield financial warfare against what it now increasingly labels as narco-terrorism.

The Financial Crimes Enforcement Network (FinCEN), the Treasurys anti-money laundering unit, designated CIBanco, Intercam Banco, and Vector Casa de Bolsa as “primary money laundering concerns” for their alleged...