WASHINGTON — The White House scolded evangelical preacher Franklin Graham for making "preposterous charges" on Easter Sunday, after he cited conspiracy theories over President Barack Obama's birthplace.

Graham, son of famed pastor Billy Graham, an advisor to presidents for decades, described Obama as a "very nice man" but appeared to give credence to charges by some conservatives the president was not born in the United States.

Asked about the charges on Monday, White House spokesman Jay Carney chose his words carefully.

"I think it's unfortunate that a religious leader would choose Easter Sunday to make preposterous charges," Carney said.

Graham was asked in the interview broadcast on Sunday to weigh in on the issue of Obama's birthplace, which has been whipped up by radical conservative groups and spawned the so-called "birther" movement.

"The president, I know, has some issues to deal with here. He can solve this whole birth certificate issue pretty quickly," Graham said.

Hawaii has released a certified copy of Obama's birth certificate. The 1961 archives of two local newspapers also show birth announcements and Obama has joked about the whole controversy in recent political speeches.

According to the US Constitution, presidents and vice presidents must be natural born citizens of the United States.

Graham also answered a question about charges by fringe Obama opponents, that the president, the son of a white American mother and a black Kenyan father, was not in fact a practising Christian but followed the Muslim faith.

"There are many people that do wonder where he really stands on that. Now, he has told me that he is a Christian. But the debate comes, what is a Christian?" Graham said in the ABC interview.

"For him, going to church means he's a Christian. For me, the definition of a Christian is whether we have given our life to Christ and are following him in faith and we have trusted him as our lord and savior.

"God is the only one who knows his heart."

Obama spent Sunday morning at Easter services at the Shiloh Baptist Church, which was founded by freed slaves, in Washington DC.

"The president took his family to church in a very high-profile way to celebrate Easter," Carney said.

"I think it was highly visible to most Americans. And he, as a devoted Christian, he believes it's a very important holiday for him personally, for his family and for Christians around the country."