(Reuters) U.S. Senate Democrats are considering legal action over President Donald Trump’s appointment of a new acting attorney general, congressional sources said on Friday, as some outside experts called the move unconstitutional.

Trump on Wednesday named Matthew Whitaker to replace former Attorney General Jeff Sessions, who was forced out after months of attacks by Trump for recusing himself from an ongoing probe into Russian meddling in the 2016 presidential election.

The move made Whitaker supervisor of the investigation, which has hung over Trump’s presidency. Whitaker has criticized the probe in the past as too wide-ranging, which has raised concerns among Democrats that Sessions’ ouster and Whitaker’s appointment might be precursors to Trump moving to end it.

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