ATLANTA (AP) - President-elect Barack Obama has weighed in on Georgia's U.S. Senate runoff, cutting a radio ad supporting Democrat Jim Martin.

In the spot, Obama thanks Georgians who voted for him Nov. 4. He adds, "The elections aren't over'' and urges voters to return to the polls Dec. 2 and cast ballots for Martin.

The ad will begin running statewide Friday.

Martin is trying to unseat incumbent Republican Sen. Saxby Chambliss, who failed to get more than 50 percent of the vote on Nov. 4, forcing the runoff.

The Georgia race has national significance because it could help the Democrats control 60 seats in the Senate.

There is an unresolved race in Minnesota between GOP Sen. Norm Coleman and Democrat Al Franken.

(Copyright 2008 by The Associated Press. All Rights Reserved.)