Cleared by a Florida jury, George Zimmerman walked free from criminal charges in the shooting death of unarmed black teenager Trayvon Martin but was still under fire from civil rights leaders and critics who were dismayed by the verdict.

Civil rights leaders in the US have demanded the arrest of a neighbourhood watch helper who went free after shooting dead an unarmed black teenager.

The Obama administration has defended its decision to force out a black Agriculture Department employee over racially-tinged remarks at a banquet, despite evidence that they were misconstrued.