Obama is hoping a Biblically-titled grassroots effort will boost his stature among South Carolina primary voters.

COLUMBIA, South Carolina (CNN) - Barack Obama's presidential campaign is hoping to increase the candidate's profile among African-American voters in South Carolina by launching a grassroots effort called "40 Days of Faith and Family."

The effort, which began on Saturday, will organize Bible study programs and gospel concerts across the state over the next month in order to engage voters and boost Obama's name identification among Palmetto State voters who may be more familiar with the Democratic frontrunner, Sen. Hillary Clinton.

Obama staffers have a significant grassroots effort underway in the state, using phone banks, canvassing and house meetings to reach out to black South Carolinians in urban centers as well far-flung rural areas. The campaign has also run radio ads here targeted at African-American voters emphasizing the Democratic candidate's faith.

African-Americans make up an estimated fifty percent of Democratic primary voters here. Recent polls have shown Obama and Sen. Hillary Clinton running neck-and-neck among black voters.

According to a release from the campaign, "40 Days of Faith and Family" is "an opportunity for people of faith to come together, across racial and denominational lines, to talk about how they live their faith outside the four walls of the church, what they want to see from their presidential candidates and how Obama’s faith informs how he thinks about the issues of our time."

The release also says the effort will emphasize Obama's experience as a community organizer and civil rights attorney, two biographical entries that the campaign hopes will help the senator appeal to black voters.

Though Obama and Clinton are in a dead heat among African-Americans, Clinton still leads Obama by a wide margin in most statewide polls.

[For more campaign news from the Palmetto State, check out the South Carolina Political Ticker.]

UPDATE: The Obama campaign clarifies that they will not be organizing Bible studies themselves, but will be doing voter outreach through existing church Bible study programs.

- CNN South Carolina Producer Peter Hamby

Hillary Clinton has launched the first radio ad of her presidential campaign.

COLUMBIA, South Carolina (CNN) - Sen. Hillary Clinton on Monday became the second Democratic presidential candidate - after Sen. Barack Obama - to hit South Carolina's radio airwaves with an advertisement targeting African-American voters.

Clinton's ad is the first radio spot released by her presidential campaign. Entitled "Invisible," the ad touches on several issues important to black voters here, such as health care, crumbling schools, and the Bush administration's response to Hurricane Katrina.

The ad argues that black voters are "invisible" to President Bush. "And if you're stuck on a rooftop or stranded in the Superdome during a hurricane, you're invisible to this president even when you're on CNN," says Clinton during the ad, plucking a line from her September 16 speech to the Charleston NAACP.

The narrator ends the ad with a theme the Clinton campaign has pushed increasingly in recent weeks: that she is the candidate of change.

The ad will run on two-dozen radio stations of "predominantly African-American listenership" across the state, according to the Clinton campaign.

Obama's radio ad, which touted the Illinois Senator as a "Christian family man" and a "soldier for justice," launched here in late July on gospel and urban stations across the state.

Listen to the Clinton ad here.

- CNN South Carolina Producer Peter Hamby