Democrats in Congress on Saturday launched an investigation into President Donald Trump's move to oust the State Department's internal watchdog, accusing the president of escalating his fight against any oversight of his administration.

Trump announced the planned removal of Inspector General Steve Linick in a letter to House of Representatives Speaker Nancy Pelosi late Friday night, making Linick the latest government inspector general to be ousted in recent weeks under the Republican president.

The top Democrats on the House and Senate Foreign Relations Committees questioned the timing and motivation of what they called an "unprecedented removal."