The group, Save the U.S. Senate PAC, will this week start airing commercials featuring Trump Jr. that are aimed at mobilizing Trump backers across Georgia. A person familiar with the plans said it would be the first in a series of commercials spotlighting Donald Trump Jr. ahead of the of the Jan. 5 vote, which will decide control of the Senate.

The super PAC will air its ads only on conservative radio and TV stations to reach Trump loyalists. The organization is investing six figures to run the first ads on radio stations statewide, and later this week it will begin cutting TV and digital commercials with the younger Trump.

Senior Republicans are alarmed that Donald Trump’s accusations of widespread voter fraud in Georgia and elsewhere, which he has not substantiated, will have the unintended side effect of discouraging his voters from turning out in the runoffs.