A coalition of African American faith leaders is invoking the words of Martin Luther King Jr. as it tries to revive the debate over the nation's gun laws and calls on Congress to toughen background checks for firearms purchases.

In an open letter timed to coincide with the 50th anniversary celebration of the March on Washington, leaders of predominantly black congregations across the country wrote that they have an obligation to future generations to "sound the clarion call to end gun violence in our communities."

"On this national anniversary, we must not only herald the progress we have made as a country, but we must take stock of the detrimental decisions and policies of indifference that turn a blind eye to the alarming magnitude of lives cut short too soon," the clergy members wrote in the letter.

They added, "As faith leaders, we write this open letter to, in the words of Dr. Martin Luther King, Jr., 'dramatize a shameful condition' -- the injustice of rampant gun violence in our communities and the staggering availability of guns to dangerous individuals."

The leaders urged Congress to pass a law requiring background checks for all gun purchases, including private sales. They wrote that gun violence afflicts African Americans disproportionately, noting that nearly 60,000 black children and teens have been killed by guns in the five decades since King delivered his "I Have a Dream" speech.

"We have eulogized victims of gun violence," they wrote in the letter. "We have provided comfort to families and counseled countless parents who have lost children senselessly to gun violence."

President Obama put gun control at the top of his domestic agenda in the aftermath of last December's elementary school massacre in Newtown, Conn. But after several months of debate in Washington and heavy lobbying from both sides, a measure to expand background checks failed to pass the Senate in April.

In the months since, neither the Senate nor the House has taken up the issue. But advocates -- including parents of the 20 small children killed in Newtown as well as former congresswoman Gabrielle Giffords (D-Ariz.), who was shot and severely injured in 2011 -- have tried to put gun violence back on the agenda on Capitol Hill.

The group of clergy members hope their letter adds to the pressure. It is signed by 56 faith leaders representing congregations from coast to coast, including Ebenezer Baptist Church in Atlanta, where King served as pastor.

"We do not want the public’s attention to this issue to be forgotten," said Rev. Delman Coates, who as president of the Black Church Center for Justice and Equality helped organize the group letter. Coates is senior pastor at Mt. Ennon Baptist Church in Clinton, a Maryland suburb of Washington.

Coates said clergy members plan to hold prayer vigils and other demonstrations next month at gun shows and other events in such states as Georgia, Texas and Virginia -- places with strong traditions of gun ownership as well as large African American populations.

“We are not anti-guns," Coates said. "There are several pastors in this coalition who are proud gun owners. We’re for responsible gun ownership."