Amid the ongoing furor over Mahmoud Ahmadinejad's disputed re-election as president of Iran, he has once again challenged President Barack Obama to a debate.

The state-run news agency in Iran carried Ahmadinejad's challenge to Obama on Sunday, while ignoring escalating unrest in the streets over the election results.

Ahmadinejad, who first challenged Obama last month, has now said "negotiations on the nuclear issue are history," but added: "As I said last month, I am ready to have a debate with the American president."

Ahmadinejad also challenged Obama several days before Friday's election, The Hill newspaper reported. He said in an interview: "I want constructive interaction on justice and respect and if I remain in the post, I will invite President Obama to a debate in the venue of the United Nations General Assembly.

"Our proposal is to sit at the U.N. and debate about the origin of the global problems and [let] each side put forward its solutions."