COLUMBUS, Ga. (AP) — A runoff is increasingly likely in Georgia's tight gubernatorial race, and both candidates are spending their time rallying their base of supporters with just over a week left before the Nov. 4 election.

Gov. Nathan Deal had rallies planned in six cities across north Georgia, home to the state's largest concentration of Republican voters. Carter spent the day in south and middle Georgia, joined by his grandfather, former President Jimmy Carter, at a rally in Columbus.

It was the 39th president's third public appearance on behalf of the campaign and he's expected to campaign in metro Atlanta this weekend.

Polls suggest neither candidate will claim a majority needed to avoid a runoff and that a third-party candidate, Libertarian Andrew Hunt, could draw up to 6 percent of the vote.