A federal regulator’s rule allowing it to issue national trust bank charters to cryptocurrency and other nontraditional companies violates federal law and should be blocked, a trade group for community banks said.

The Independent Community Bankers of America said the Office of the Comptroller of the Currency is improperly giving national charters allowing cryptocurrency companies to engage in banking activities beyond the custody and other fiduciary services trust banks typically perform. The group filed a complaint Friday in the US District Court for the District of Columbia.

“Congress did not create the national trust charter as a side door into …