Health and Human Services Secretary Kathleen Sebelius violated federal law by using her Cabinet position to campaign for President Obama, federal investigators said Wednesday.

The Office of Special Counsel (OSC) said Sebelius broke federal law by saying in a February speech that it is “imperative” to reelect President Obama. She also used the speech, delivered at a Human Rights Campaign event in Charlotte, N.C., to plug local Democrats.

The OSC said Sebelius violated the Hatch Act, which prohibits federal employees from campaigning while acting in an official capacity.

Republicans criticized Sebelius in the wake of the OSC report, but stopped short of calling on her to step down.