CHARLOTTE, N.C. -- President Barack Obama says "America does not forget" and is vowing justice for the murder of an American journalist.

The president said the country continues to grieve James Foley, killed last week by Islamic State militants.

Obama called the killers "barbaric terrorists." He signalled that a response may take some time.

He said -- quote -- "Rooting out a cancer like ISIL won't be easy and it won't be quick."

But he said America is patient and "justice will be done."