SPRINGFIELD, Ill. (AP) — The Illinois treasurer has sent President Donald Trump a letter urging him to give clear guidance to the banking industry about medical marijuana.

State Treasurer Michael Frerichs issued a news release Monday saying Trump’s approach will be crucial to the continuing availability of medical marijuana in Illinois.

Federal law prohibits banks from processing money used in the legal cannabis industry. Frerichs says this makes it difficult for businesses to get loans and restricts customers to cash-only transactions.

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Under President Barack Obama, the Justice Department stated it would not make enforcement a priority, knowing that many states had legalized some cannabis use.

Frerichs’ letter to Trump urges him to give assurance that responsible financial institutions will not face penalties or prosecution for conducting business with state-licensed cannabis cultivators and dispensaries.