Washington - Racism is driving the recent anger-charged criticism of President Barack Obama, ex-president Jimmy Carter said on Tuesday.

"I think that an overwhelming proportion of the intensely demonstrated animosity toward President Barack Obama is based on the fact that he is a black man, he's African-American," Carter, 84, told NBC television.

"I live in the South, and I have seen the South come a long way," Carter added.

"But that racism inclination still exists, and I think it has bubbled up to the surface because of a belief among many white people, not just in the South but across the country, that African-Americans are not qualified to lead this great country."

"It is an abominable circumstance, and grieves me and concerns me deeply," added Carter.

Carter's remarks come after a week in which a Republican lawmaker Joe Wilson shouted "You lie" at the US president during a speech, and thousands protested against Obama administration policies in Washington.

A series of Democratic lawmakers and political columnists have pointed to the trends - the heckling, the gun-toting, the preachers leading congregations in prayers that Obama will die - and warned of the danger therein.

By News24