The ouster of Attorney General Jeff Sessions by President Donald Trump on Wednesday drew sharp criticism from Democrats, who warned Trump against moving to squash a probe into Russian meddling in the 2016 U.S. presidential election.

The probe, led by special counsel Robert Mueller under the supervision of the Justice Department, has clouded the Trump presidency. The president had long complained about Sessions recusing himself from supervising Mueller.

Democrats raised concerns about Sessions' acting replacement, Matthew Whitaker, who now oversees Mueller and once argued Mueller's probe was going too far. They also questioned whether the removal of the top U.S. law enforcement officer was an attempt to undermine or end the investigation.