US Attorney General Eric Holder has called for a rethink of "stand-your-ground" laws following the acquittal of a neighbourhood watch volunteer who fatally shot an unarmed black teenager in Florida.
Addressing the National Association for the Advancement of Colored People (NAACP), Holder acknowledged the passions stirred by the racially-tinged trial of George Zimmerman, found not guilty on Saturday of murdering Trayvon Martin.
"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 neighbourhoods," Holder said.
"These laws try to fix something that was never broken. There has always been a legal defence for using deadly force if -- and the "if" is important -- no safe retreat is available."
Zimmerman's trial lawyers did not explicitly invoke Florida's stand-your-ground law, arguing instead that he acted in self-defence in a confrontation with Martin in February last year.
But the case has stirred up controversy around such laws, which assert that citizens can use lethal force if they feel their lives are threatened.
"By allowing and perhaps encouraging violent situations to escalate in public, such laws undermine public safety. The list of resulting tragedies is long and - unfortunately - has victimised too many who are innocent," Holder said.
"It is our collective obligation - we must stand our ground - to ensure that our laws reduce violence, and take a hard look at laws that contribute to more violence than they prevent."
Critics of the verdict from the six-woman and mostly white jury argue that Zimmerman had racially profiled Martin -- who had no criminal record -- and was able to kill him with impunity because of a biased criminal justice system.
Holder, who spoke at the NAACP national meeting in Orlando, Florida, not far from where Martin died, remained non-committal on whether the Justice Department might pursue Zimmerman on civil rights grounds.
"The Justice Department has an open investigation" into the case, he said.
"While that inquiry is ongoing, I can promise that the Department of Justice will consider all available information before determining what action to take."