US election 2016: Trump and Romney's break-up battles
They used to be in a happy relationship, but now Mitt Romney and Donald Trump are going through a very bitter - and public - break-up.
Here are three of the insults the 2012 Republican presidential nominee hurled at his former friend - along with the current front-runner's typically bombastic responses.
Produced by the BBC's Olivia Lace-Evans
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