US hostage Kassig's parents appeal for 'mercy'

The parents of US hostage Peter Kassig have appealed to Islamic State militants to "show mercy" and release him.

In a video statement, Ed and Paula Kassig said they were proud of their son and the humanitarian aid work he had done.

It follows the release of a video by the militant group on Friday, which showed the beheading of British aid worker Alan Henning.

That video ended with a threat to kill 26-year-old Mr Kassig.

It is believed Mr Kassig changed his given name to Abdul-Rahman and converted to Islam while in captivity.