WASHINGTON —  Former President Clinton said Tuesday that one of his "great regrets" was failing to do more to bridge the economic and social gaps between white and black people in the United States.

Speaking to a black think tank, the former president offered a somber, sorrowful reflection on the end of his time in the White House and his failed effort to spark a national debate about race relations.

The current debate in the country over immigration, Clinton told the Joint Center for Political and Economic Studies, is further proof important racial problems have yet to be solved.

"The idea that I live in a country I spent my lifetime trying to make better, but there's still hundreds of thousands, maybe millions of people, most of them people of color, who will die before their time, drop out of school, go to prison, never have a chance to live their dreams, is galling and painful to me," Clinton said.

"One of the great regrets of my public life is that for all the progress we made in so many areas we are still losing so many of our young people of color, disproportionately African-American males," he said.

The former president urged private citizens to take action on racial issues, saying disasters like the tsunami in Asia and Hurricane Katrina show non-governmental organizations can rebuild and improve society.

"I don't know how you have a great country that is a beacon of hope for the world for peace and freedom and democracy if you let a third of any group of people wind up going to prison sometime in their lives," said Clinton.

A 2005 government report found that 8.4 percent of the country's black men between the ages of 25 and 29 were in state or federal prison, compared with 2.5 percent of Hispanic men and 1.2 percent of white men in the same age group.

Blacks made up an estimated 41 percent of inmates with a sentence of more than one year, the report said.

Clinton's reflective tone came at the end of a mostly upbeat speech peppered with funny political anecdotes and self-deprecating references to old battles. At one point, the former president said he's "already made enough people mad in my life."

At a New York City fundraiser the previous night, Clinton referred to himself as "the world's most famous sinner" — a line he has used before to refer to the affair with Monica Lewinsky that led to impeachment.