COLUMBIA, S.C. -- Two black South Carolina ministers listed by Barack Obama as supporters of his campaign say they never endorsed the Illinois senator, while at least two others say they affirmed their support only after being contacted by the campaign when questions were raised over their endorsements.

Hillary Clinton, too, has stumbled when it comes to claiming the support of the clergy. And with just over a week to go until Iowa's first-in-the-nation caucuses, the questions over endorsements coincide with gambits by the two frontrunning Democrats to pick off each other's supporters and win them over to their sides.

The moves suggest that every endorsement, however low-key, counts -- but the enthusiastic head-counting has had its drawbacks.

Earlier this month, Obama's campaign released a list of what it said were nearly 130 senior pastors in South Carolina endorsing his run for the Democratic nomination. When contacted by The Associated Press, several ministers said they have yet to decide who will get their vote and were unclear how they ended up on the Illinois senator's list.

"I really haven't decided to endorse him yet. I was thinking about it," said the Rev. Clifford Gaymon of Zion Hill Missionary Baptist Church in rural Clarendon County.

An Obama spokeswoman said the list was created after campaign organizers called ministers and asked to release their names publicly.

"We used all our resources to ensure we had the most accurate and up-to-date list, and we worked to check with everyone on the list," said South Carolina spokeswoman Amaya Smith. "It's a pretty long list of people."

But some ministers said their names were used without their permission. Gaymon, mistakenly listed as retired on the Obama list, said he's been to campaign events to find out more about the presidential candidate, but did not receive a phone call about making an endorsement.

The Rev. Michael Blue of Door of Hope Christian Church in Marion was added to the list without permission and has asked the Obama campaign to take his name off the list, said church spokesman Ronnie Green.

Clinton ran into some of the same questions after her campaign released its list of endorsements from black ministers late last month.

Blacks compose nearly half the Democratic primary vote in South Carolina, and the candidates are looking for an edge with the critical voting bloc.

The majority of people endorsing each candidate was accurate, according to the AP reviews, and many supporters said they are eager to lend a hand.

Both campaigns lists' had some sloppy record keeping: misspelled names, churches listed in incorrect cities and beside incorrect names. But, like Clinton's list, Obama has some other substantial inconsistencies.

When Obama's campaign released its list of ministers Dec. 4, it said everyone on it was a senior pastor, unless otherwise noted. That meant there were 122 senior pastors and three associate pastors of different churches and ministries, including four retirees.

Before supplying a second list to the AP a day later, the campaign withdrew two names and added one, and noted a fourth associate pastor. The AP review found at least two more associate pastors and a youth pastor's assistant.

The Clinton and Obama campaigns also got into an endorsement spat Wednesday, with each claiming to have converted a former supporter of the other.

Clinton's campaign spotlighted Iowa ironworker and former Obama labor steering committee member Bob McFadden, announcing Wednesday that he has switched his support to Clinton.

"Hillary Clinton won't just talk the talk -- she cares about the issues important to all of us and will work to change the direction of our country," McFadden said in a Clinton campaign statement.

Obama countered, announcing that Army veteran Kent Sovern, formerly the Iowa co-chairman for Clinton's Veterans Committee, has defected to caucus for Obama.

Clinton and Obama got into another sparring match over the weekend over who can lay claim to the backing of members of the Bill Clinton administration.

Obama suggested Friday in Iowa that he has more Clinton-era foreign policy experts backing his candidacy over Clinton's. But when asked to cough up the hard numbers, Clinton's campaign provided 85 names, while Obama's provided 47.

On Wednesday, the Clinton campaign released a list of more than 200 foreign policy experts and former officials who are supporting the New York senator for president. More than 150 of them served in Bill Clinton's administration. Among some of the notables were former Secretary of State Madeleine Albright and former Supreme Allied Commander of Europe and 2004 presidential candidate Wesley Clark.

Click here for a list of Clinton's foreign policy supporters.

Clinton tried to play down the endorsement aspect of the campaign Saturday in New Hampshire.

"But this is not a campaign between lists of advisers. This is a campaign between real people, with experience and qualifications to become president on day one," she said.

The Associated Press contributed to this report.