Montana Gov. Steve Bullock (D) sued the IRS on Tuesday to block a new policy no longer requiring some non-profits to reveal their donors.

The lawsuit, filed in Montana federal district court and first reported by The New York Times, alleges that the agency improperly implemented the new donor disclosure rules and has "unlawfully interfered with Montana's ability to gather data that the state needs in order to administer its tax laws."

At issue is a Montana law that blocks the state from granting tax-exempt status to groups whose income benefits private shareholders, which Bullock claims officials will struggle to enforce without access to the IRS donor data.

The governor also alleges that the policy was implemented without allowing states to weigh in on the new practice or providing "a reasoned analysis of the decision to relieve tax-exempt organizations."

The Hill has reached out to the Treasury Department for comment.

Bullock told the Times that the Trump administration is "playing fast and loose with Treasury procedures."

"The goal of the litigation is to make sure that dark money and foreign money isn't flowing into our elections unchecked," he said.

The Treasury Department announced last week that some tax-exempt groups would no longer be required to hand over the names and addresses of donors to the IRS.

Those organizations include 501(c)(4) groups that lobby for specific policies, like the National Rifle Association and the Koch brothers-backed Americans for Prosperity.

"Americans shouldn't be required to send the IRS information that it doesn't need to effectively enforce our tax laws, and the IRS simply does not need tax returns with donor names and addresses to do its job in this area," Treasury Secretary Steve Mnuchin said in a statement last week on the new policy.