Republicans seized on revelations that Sen. Max Baucus (D-Mont.) nominated his girlfriend to a U.S. attorney position, calling for a Senate Ethics Committee investigation.

Republican National Committee (RNC) Chairman Michael Steele called for an official investigation into Baucus, who allegedly flagged Justice Department lawyer Melodee Hanes for a U.S. attorney nomination while engaging in a romantic relationship with her. Hanes eventually withdrew her name from consideration.

"Today's report that Senator Max Baucus used his Senate office to advance a taxpayer funded appointment for his staff-member girlfriend raises a whole host of ethical questions," Steele said in a statement. "This issue demands the attention of the Senate Ethics Committee."

Senate Republicans have refrained so far from issuing statements condemning Baucus, the chairman of the Senate Finance Committee whose position has made him an integral figure in both healthcare and climate change legislation before Congress.

Baucus's relationship with Hanes had been relatively well-known following the senator's filing for divorce from his wife earlier this year. Baucus denied Saturday that the relationship with Hanes was an "affair."

"They should hold a hearing to identify who was involved in this process, what they knew and when they knew it, and why Senator Baucus put his personal needs above those of the people of Montana," Steele said of the Senate Ethics Committee.

Senate Minority Leader Mitch McConnell (R-Ky.) was asked about the matter at a healthcare press conference Saturday, but had no comment.