Democrats are starting to join in the outrage over the Internal Revenue Service's targeting of conservative groups.

Monday morning, Senate Finance Committee Chairman Max Baucus (D-Mont.) and Sens. Tim Kaine (D-Va.) and Joe Manchin (D-W.Va.) all issued statements denouncing the IRS and calling for an investigation and corrective action.

“These actions by the IRS are an outrageous abuse of power and a breach of the public’s trust. Targeting groups based on their political views is not only inappropriate but it is intolerable," Baucus said, adding: "The IRS will now be the ones put under additional scrutiny.”

Manchin called the IRS's actions "un-American" and urged President Obama to denounce them.

“The actions of the IRS are unacceptable and un-American," he said. "Government agencies using their bureaucratic muscle to target Americans for their political beliefs cannot be tolerated. The president must immediately condemn this attack on our values, find those individuals in his Administration who are responsible and fire them."

Added Kaine: "There’s no excuse for ideological discrimination in our system. The Administration should take swift action to get to the bottom of this to ensure those responsible for misconduct are held accountable and establish appropriate safeguards to prevent this from ever happening again."

Obama is expected to address the issue at a news conference Monday morning.

Updated at 11:27 a.m.