ORLANDO, Fla. -

Attorney General Eric Holder on Tuesday strongly criticized stand-your-ground laws that allow a person who believes he is in danger to use deadly force in self-defense.

Holder spoke at the NAACP convention in Orlando, saying it is time to question laws that "senselessly expand the concept of self-defense."

Referring to the case of Trayvon Martin shooting, Holder said: "separate and apart from the case that has drawn the nation's attention, it's time to question laws that senselessly expand the concept of self-defense and sow dangerous conflict in our neighborhoods."

The attorney general said the country must take a hard look at laws that contribute to "more violence than they prevent."

Holder said such laws "try to fix something that was never broken."

The Justice Department is facing pressure to file federal charges in the Martin killing. George Zimmerman was acquitted on Saturday of second-degree murder in Martin's death.

Civil rights groups are planning nationwide vigils, and hundreds of thousands of people support an online petition drive calling for Zimmerman to face federal charges in the February 2012 killing.

"I believe that this tragedy provides yet another opportunity for us to speak honestly about the complicated and emotionally charged issues that his case has raised," Holder said.

NAACP is pushing for the petition drive. Holder is scheduled to speak at 4:30 p.m.

On Wednesday, Rev. Al Sharpton, Rev. Jesse Jackson and Martin Luther King III will be at the convention for a session on voting rights.

Meanwhile, State Sen. Geraldine Thompson called on Gov. Rick Scott to address the Zimmerman verdict.

"Florida needs to address the underlying problem of perceptions of disparities in the use of deadly force among minority populations in Florida," Thompson said in a news release. "To calm the minority angst regarding the Zimmerman verdict, Florida must do more than heighten police presence and prepare to fill jail cells with protesters. We must deal honestly with minority Floridians' mistrust of Florida's judicial system."

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