On a day that saw Obama's wife, Michelle, also forced to backtrack during an interview in which she termed herself a "busy, single mother," the White House said the president telephoned Kamala Harris to say sorry.

"The president did speak with Attorney General Harris last night after he came back from his trip, and he called her to apologize for the distraction created by his comments," spokesman Jay Carney told reporters.

"They are old friends and good friends, and he did not want in any way to diminish the attorney general's professional accomplishments."

Obama made the remarks on Thursday during a fundraiser for his Democratic Party in the Golden State.

His slip-of-the-tongue came after he lauded Harris as brilliant, dedicated and tough as he introduced her at the event.

"She is exactly what you'd want in anybody who is administering the law, and making sure that everybody is getting a fair shake. She also happens to be by far the best-looking attorney general in the country," he said.

On Friday, Carney noted that Obama's "best looking" remark about Harris came after the series of comments that praised her effectiveness as a prosecutor, but critics said the president's conduct was nevertheless inappropriate.

"It's not a compliment. And for a president who has become a cultural model for many of his supporters in so many other ways, the example he's setting here is disgraceful," said Jonathan Chait, of New York Magazine.

The first lady, meanwhile, also ran into trouble when speaking to a CBS News affiliate in Vermont about the strains of being a working parent.

"Believe me, as a busy single mother," she said, before correcting herself.

"I shouldn't say single. As a busy mother. Sometimes, you know, when you've got a husband who is president, it can feel a little single. But he's there."