ATLANTA (CNN) -- Former Massachusetts Gov. Mitt Romney picked up a telephone Wednesday night and joined volunteers in a phone banking effort to recruit 24,000 new supporters to his presidential campaign in a 24 hour period.

The effort is part of the Republican presidential hopeful's "Sign Up America!" program that began during Tuesday's GOP presidential debate. As of Wednesday night, Romney said the effort had drawn more than 16,000 new people into his campaign.

"A campaign is not just won and lost in the air wars," Romney told supporters in a speech captured by CNN Boston affiliate WHDH. "It's the ground wars if you will. People who are willing to pick up the phones and call their neighbors, get people out to vote, put on the bumper sticker, send in the check for $10.

"That's ultimately just as important," he added.

The former governor also told the group that during the South Carolina Republican Party debate there were nearly 1,000 viewing parties held by supporters in 48 states including 55 in Iowa and 41 in New Hampshire -- two crucial states in the presidential nominating process. Lawrenceburg, Indiana, claimed the title for the largest single gathering at 60 people, he said.

-- CNN Political Desk Editor Jamie Crawford