US Senate majority leader Harry Reid has apologised for private comments he made about Barack Obama before the 2008 presidential election.
Senator Reid is quoted in a new book as predicting Mr Obama could win since he was a "light-skinned" African-American "with no Negro dialect", unless he wanted one.
The Democrat politician said he now regretted "using such a poor choice of words" and apologised to any Americans offended.
The BBC reports President Obama has accepted the apology and said "the book is closed".
However, Republican Senators have demanded his resignation.
Correspondents say Senator Reid, 71, is facing a difficult re-election battle in his home state of Nevada in the mid-term elections in November.
The book is Game Change, by journalists Mark Halperin and John Heileman. An extract was published by The Atlantic magazine on Friday.