U.S. Senator Sam Brownback has called on the U.S. Treasury Department to designate North Korea as a primary money laundering concern.

The hawkish Republican lawmaker issued a news release Wednesday, calling for the most stringent measures against Pyongyang under the U.S. Patriot Act.

Brownback claimed North Korea’s major financial support comes from money laundering, counterfeiting, drug trafficking and massive insurance fraud. He urged the U.S. government to take every measure to block the North’s illicit revenue sources and cash inflow.

In accordance with the Patriot Act, the U.S. Treasury has the authority to list a nation or a nonstate actor as a primary money laundering concern and completely block its access to the U.S. financial system. Currently, Myanmar and Nauru are on the list.

Following the North’s long-range missile launch in April, Brownback submitted a bill to the U.S. Congress to place the communist country back on the U.S. terrorism blacklist and revive related sanctions.