WASHINGTON -

First lady Michelle Obama says her "heart goes out to the parents" of 17-year-old Trayvon Martin, the unarmed teenager who was fatally shot by a neighborhood watch volunteer in Florida.

Mrs. Obama says in an interview with NPR that all parents understand "the tragedy of that kind of loss." Martin was shot by neighborhood watch volunteer George Zimmerman, who has claimed self-defense.

The first lady says it's important "not to lose sight of the fact that this is a family that's grieving and there's been a tremendous loss." She says, "we all have to rally around that piece of it."

Police initially didn't charge Zimmerman in the Sanford, Fla., shooting, leading to nationwide protests. Zimmerman was charged with second-degree murder last week.