Civil rights issue

At the White House on Friday, US President Barack Obama sided with those who say the shooting need not have happened, expressing sympathy to the Martin family. He said the case was properly handled by the court in Florida but questioned "stand-your-ground"laws that have been adopted in 30 states.

About 2,000 people attended the Trayvon Martin Prayer Vigil and Rally in downtown Atlanta, where speakers urged the crowd to register to vote and to seek repeal of Georgia's stand-your-ground law.

Singer Beyonce and her husband, rapper Jay Z, depart from a rally for Trayvon Martin in New York on Saturday. Carlo Allegri / Reuters

Martin Luther King III urged the audience to go to Washington on Aug. 24 for the 50th anniversary of the March on Washington and his father's famous "I Have a Dream"speech. "It's marching time, ladies and gentlemen,"he said.

At a rally in Miami, Martin's father, Tracy, told supporters that after the acquittal he has "come to realize George Zimmerman wasn't on trial — Trayvon was on trial".

In Los Angeles, about 500 people converged on the federal courthouse, toting signs saying "Open Season on the Black Man"and "This Should Not Be OK in 2013 America".

In Chicago, some 500 people rallied across from the Everett McKinley Dirksen federal courthouse.

"We are standing up here today to say to our young people, ‘we value your lives,'"said Chicago Urban League Chief Executive Officer Andrea Zopp, who has a 17-year-old son. "The civil rights movement is not over."