WASHINGTON (AP) — An internal watchdog says he's investigating the Treasury Department's actions in handling Congress' request for President Donald Trump's tax returns in a long-running legal battle.

The acting inspector general of the Treasury Department, Rich Delmar, says in a statement his office is conducting the probe in response to a request from Rep. Richard Neal.

Neal, a Massachusetts Democrat and chair of the House Ways and Means Committee who asked for Trump's returns last spring, told Delmar he's seeking assurance that no one is intimidating or blocking government employees carrying out their duties.

Treasury Secretary Steven Mnuchin has refused to hand over Trump's returns, maintaining that the Democratic-controlled House is seeking them for political purposes. The Democrats say they're needed for legitimate congressional oversight.