Sen. Thom Tillis said he will not support Kevin Warsh’s nomination to lead the Federal Reserve unless the DOJ drops its investigation into current Fed Chair Jerome Powell.

The probe focuses on alleged cost overruns in Fed building renovations, which Tillis suggested are not serious enough to justify the inquiry.

He argued the investigation, led by federal prosecutors, is interfering with a routine transition at the central bank.

Powell has said he will remain in his role while the investigation continues, despite legal challenges to subpoenas in the case, The Hill has reported.

Tillis urged officials to end the probe so the Senate can move forward with confirming Warsh.