WASHINGTON (REUTERS) - America is struggling to fully realise the vision that civil rights leader Martin Luther King described in his famous "I have a dream" speech 50 years ago, as the goal of economic security for all remains elusive, President Barack Obama said on Wednesday.
Mr Obama, the first black United States (US) president, spoke to thousands of marchers on Washington's National Mall on Wednesday to commemorate King's landmark address, which came to symbolise the struggle for equality among blacks and whites in America.
Mr Obama said King's speech inspired millions of Americans to fight for a more just society and rights that people now take for granted.
"To dismiss the magnitude of this progress, to suggest, as some sometimes do, that little has changed, that dishonors the courage, the sacrifice of those who paid the price to march in those years," Mr Obama said.
"But we would dishonour those heroes as well to suggest that the work of this nation is somehow complete," he said, calling economic justice the "unfinished business" of the civil rights battle.
Marchers, many wearing T-shirts with King's face on them, began their walk near the US Capitol.
They were led by a line of military veterans and people who had been at the 1963 march, their arms linked. People sang We Shall Overcome and other civil rights anthems.
Fighting restrictive voting rights laws that Democrats say hurt minorities, combating joblessness and reducing gun violence among African Americans are among the issues that civil rights leaders put at the forefront of their efforts in 2013.
"This march was supposed to be about jobs, but it's about a lot more," said marcher Ash Mobley, 27, of Washington, who said she was there to represent her grandmother, who had been at the 1963 event.
The marchers heard speeches from former presidents Bill Clinton and Jimmy Carter and members of King's family on the steps of the Lincoln Memorial, the site of King's address on Aug 28, 1963.
A bell rang at 3pm EDT (3am Singapore time), 50 years to the minute after King ended his clarion call of the civil rights movement with the words "Let freedom ring." Ms Bernice King, his youngest child, urged the crowd to stay true to the ideals enunciated by her father.
"If freedom is going to ring in Libya, in Syria, in Egypt, in Florida, then we must reach across the table, feed each other and let freedom ring," she said.
ECONOMIC GAP PERSISTS
Mr Obama's address commemorating King, a Nobel Peace Prize winner and advocate of non-violence, comes as the White House edges closer to launching military strikes in Syria in response to what US officials say they believe was a chemical weapons attack by the Syrian government on civilians.
Mr Obama has said the country's history of racial discrimination had contributed to a persistent economic gap between blacks and whites in the decades since King's speech.
Mr Obama, whose mother was white and whose father was black, has sometimes seemed reluctant to weigh in on persistent racial divides in the US, but he spoke forcefully about the issue last month after the man who killed black Florida teenager Trayvon Martin was acquitted.
The Let Freedom Ring And Call To Action ceremony comes as almost half of Americans say much more needs to be done before the color-blind society King envisioned is realised.
Wednesday's event caps a week-long celebration of King's historic call for racial and economic justice. They included a march on Saturday that drew thousands of people urging action on jobs, voting rights and gun violence.
King's speech is credited with helping spur passage of sweeping civil rights laws. A white prison escapee assassinated him in 1968.