US death row inmate Joseph Wood has died after an execution in Arizona took nearly two hours to kill him.

Wood, a double murderer, was executed by lethal injection.

His lawyers filed an appeal for an emergency stay of execution, after he had been "gasping and snorting for more than an hour" in the death chamber.

Arizona Governor Jan Brewer says she has ordered a full review of the execution, although she said that Wood "died in a lawful manner".

Richard Lister reports.