Rev. Franklin Graham apologized Tuesday to President Obama for raising doubts about his Christian faith.
The evangelist also said religion had nothing to do with his decision not to support the president's re-election.
Graham's apology came after a group of prominent black religious leaders criticized him for saying he did not know whether Obama is a Christian and suggesting that Islamic law considers him to be a Muslim.
"We can disagree about what it means to be a Christian engaged in politics, but Christians should not bear false witness," the NAACP statement said. "We are also concerned that Rev. Graham's comments can be used to encourage racism."
Graham, president of the charity aid organization Samaritan's Purse, said he accepts Obama's declarations that he is a Christian.
"I regret any comments I have ever made which may have cast any doubt on the personal faith of our president, Mr. Obama," he said in a statement.
"I apologize to him and to any I have offended for not better articulating my reason for not supporting him in this election -- for his faith has nothing to do with my consideration of him as a candidate," Graham continued.
Graham said he objects to Obama's policy stances on abortion and same-sex marriage, which the evangelist considers to be in "direct conflict" with scripture.
When asked in a recent MSNBC interview if Obama was a Christian, Graham responded, "I cannot answer that question for anybody."
He went on to say that because Obama's father was a Muslim, "under Islamic law, the Muslim world sees Barack Obama as a Muslim."
By contrast, Graham said there is "no question" that GOP presidential candidate Rick Santorum is a "man of faith" because "his values are so clear on moral issues."
Santorum has also faced criticism for saying the president has a "phony theology" that is unbiblical.