WASHINGTON: US President Barack Obama played bartender-in-chief on Thursday at a "beer summit" of the main players in a racially charged case that he hoped would be a "positive lesson" in a national dialogue on race.

Obama, the first black US president, said it was a "friendly, thoughtful" conversation over beer at the White House with prominent Harvard scholar Henry Louis Gates, who is black, and police Sergeant James Crowley, who is white.

Crowley arrested Gates, a well-known documentary filmmaker, for disorderly conduct on July 16 after a confrontation at the professor's home, sparking a media frenzy as Gates, 58, accused the policeman of racial profiling. Crowley, who had taught courses against racial profiling, denied that.