The Donald Trump administration on Tuesday imposed sanctions on an Iranian foreign currency exchange house and what it said were front companies overseeing transactions on behalf of Iranian banks as the US maintains pressure on Tehran.

The move came after Iran ‌said its latest peace proposal to the United States over the US-Israeli led war that started February 28 involved ending hostilities on all fronts including Lebanon, the exit of US forces from areas close to Iran, and reparations for destruction caused by the conflict.

The Treasury Department imposed sanctions on the Iran-based Amin Exchange, also known as Ebrahimi and Associates Partnership Company, which it ⁠said has a widespread network of front companies spanning multiple jurisdictions, including in the United Arab Emirates, ‌Turkey and Hong Kong.

The US also blocked 19 vessels it said were involved in shipping Iranian petroleum and petrochemicals to foreign customers.

The Treasury Department said Iranian exchange ‌houses facilitated billions of dollars in foreign currency transactions a year, enabling the government to ⁠evade sanctions and ⁠access the international financial system. It said the front companies oversaw hundreds of millions of dollars in transactions on behalf of Iranian ‌banks.

“Iran’s shadow banking system facilitates the illicit transfer of funding for terrorist purposes,” Treasury Secretary Scott Bessent said in a release.