A group of US lawmakers, including Senators Elizabeth Warren and Roger Marshall, wrote a letter to top government officials on April 28 expressing grave concerns about the use of digital currencies like Tether by countries such as Russia, Iran, and North Korea to evade international sanctions.

They emphasized the urgency of strengthening regulations surrounding cryptocurrencies to combat the sophisticated methods used by rogue nations. The letter cited instances of Russia using Tether to acquire dual-use technology and sustain military actions in Ukraine, despite sanctions.

It also raised concerns about Russia's use of crypto to purchase weapons from China and North Korea and Iran's use of digital currencies to finance terrorist organizations. Lawmakers are requesting a detailed briefing on actions taken and potential strategies to mitigate these risks, highlighting the need for additional legislative and regulatory tools to safeguard national security.

This letter builds on earlier requests from the Treasury for new authority to regulate crypto exchanges and address the use of crypto in illicit activities. Elizabeth Warren has been active in proposing legislation to regulate crypto, notably with her Digital Asset Anti-Money Laundering Act.