Kentucky Gov. Andy Beshear called on Sen. Mitch McConnell to either publicly demonstrate he is able to continue serving or resign from the Senate.

Beshear criticized McConnell’s absence while he recovers from a fall and pneumonia, saying important national issues require his involvement.

McConnell’s office said he is undergoing physical therapy and working toward returning to his full Senate schedule.

Beshear also urged Senate Majority Leader John Thune to investigate McConnell’s condition if he does not provide proof of his ability to serve, ABC News has reported.

McConnell’s office has not responded to Beshear’s demands, and Kentucky law limits the governor’s ability to appoint a temporary replacement if the seat becomes vacant.