Iranian President Mahmoud Ahmadinejad has accused his election rivals of adopting smear tactics used by German dictator Adolf Hitler and says they could face jail for insulting him.
Mr Ahmadinejad was speaking at a rally in Tehran on the final day of an increasingly bitter and hard-fought election campaign.
He is facing a growing challenge from moderate former prime minister Mirhossein Mousavi.
Mr Mousavi and the two other candidates say Mr Ahmadinejad has lied about the state of the economy, which is suffering from high inflation and a fall in oil revenues.
Mr Ahmadinejad said his rivals have broken laws against insulting the president.
The semi-official Fars news agency quoted him as saying that such insults and accusations against the government are a return to Hitler's methods of repeating lies and accusations until everyone believes them.