Update:

From this report in The Guardian, it seems the hanged man, who is on life support, will not be re-executed. Original story below:

A convicted drug smuggler was pronounced dead after hanging from the gallows for 12 minutes, but his family discovered in the morgue that he was still breathing.

State media reports the man is in a coma, while Iranian authorities decide what to do next. The justice minister is content with one execution, but the decision is not his.

BBC: The government has no direct control over the judiciary which has to decide whether a second execution takes place. Iran has one of the highest rates of execution in the world. The 37-year-old convicted drug smuggler, named as Alireza M, was found alive in a morgue after being hanged at a jail in the north-eastern city of Bojnord last week. Read more

— Posted by Peter Z. Scheer