U.S. President Barack Obama will give the keynote address at Wednesday's observance of the 50th anniversary of the March on Washington, the historic 1963 demonstration for equal rights that drew more than 250,000 people to the Lincoln Memorial.
Mr. Obama, the nation's first black president, will deliver his remarks to tens of thousands of people attending the commemoration.
Civil rights leader Reverend Joseph Lowery was among those who spoke early in the day. He said he is thankful the country has a president who understands the values expressed in Reverend Martin Luther King Jr.'s famous "I Have a Dream" speech that capped the march 50 years ago. But he said the work for civil rights continues.
"We ain't going back! We have come too far, marched too long, prayed too hard, wept too bitterly, bled too profusely and died too young to let anybody turn back the clock on our journey to justice."
Also appearing at Wednesday's anniversary observance will be former presidents Jimmy Carter and Bill Clinton.
The Reverend Martin Luther King Jr.'s famous "I Have a Dream" speech urged racial harmony and justice. It was hailed by historians as one of the greatest ever delivered.
The 1963 "March on Washington for Jobs and Freedom" was held at the height of the American civil-rights movement that was aimed at ensuring the rights of all people are equally protected by the law. The movement had faced strong and sometimes violent resistance to ending the practice of segregation that treated white and black Americans differently under the law.