Gary Blodger of Oakland, California (L) and Sweetgrass Longhouse of Berkeley, California listen to a speaker before a march to protest the verdict in the George Zimmerman trial in Oakland, California July 20, 2013.[Photo/Agencies]

WASHINGTON - Protesters in multiple cities across the United States Saturday gathered to call for justice for Trayvon Martin, the black teenager who was killed by a neighborhood watch volunteer last year.

Protests were held in cities such as Washington, New York, Miami and Los Angeles. National Action Network, which organized the rallies, said more than 100 cities joined the nation-wide protests. The protesters were calling for a federal civil rights investigation as well as changes to gun regulations around the country - particularly "stand your ground" laws that allow leeway for someone to use deadly force when threatened.

In Washington, a few hundred people gathered outside a federal courthouse to express their displeasure with the acquittal of George Zimmerman, the neighborhood watch volunteer who fatally shot Martin last February.

By afternoon, the biggest action were seen in New York and Miami. In New York, Martin's mother Sybrina Fulton was joined by civil rights leader Al Sharpton and pop stars Jay Z and Beyonce.

Local reports said she told the crowd of supporters that she has moved on from the verdict and is ready to start a new chapter, but calling for the change of the "stand your ground" laws.

Similar protest took place in Miami, and was attended by Martin 's father Tracy, who told supporters that "I'd like the world to know that Trayvon was my son. He was a loved child. He did nothing wrong and we're not going to let them persecute him the way that they have."