A federal judge on Friday quashed Justice Department subpoenas issued to the Federal Reserve in January, a severe blow to an investigation that has already attracted strong criticism on Capitol Hill.

Judge James Boasberg said that a "mountain of evidence suggests" that the purpose of the subpoenas was simply to pressure the Fed to cut its key interest rate, as President Donald Trump has repeatedly demanded.

Fed Chair Jerome Powell revealed the investigation Jan. 11, prompting Sen. Thom Tillis, R-N.C., to block consideration of Trump's pick to replace Powell as Fed chair when his term expires May 15.