TEHRAN, May 25 (Xinhua) -- Iranian President Mahmoud Ahmadinejad invited U.S. President Barack Obama for a debate in the United Nations.

    "Our proposal (to President Obama) is to sit at the UN and debate about the origin of the global problems and each side put forward its solutions," Ahmadinejad said in a press conference here on Monday.

Iranian President Mahmoud Ahmadinejad waves to journalists in Tehran May 24, 2009

 "If I am elected by the great Iranian nation (as president in the upcoming presidential elections), I will repeat my invitation to Mr. Obama to have a debate in the UN to study the origin of the global issues and the management of the world for international peace," he stressed.

    Earlier, Ahmadinejad had invited U.S. ex-president George W. Bush to participate in a live debate with him in the United Nations over global diversified issues, but Bush did not give response to his invitation.

    Ahmadinejad told reporters that his congratulation to Obama upon his victory in the U.S. presidential elections was a "great gesture" to him.

    Iran is waiting for U.S. changes not in words but in practice, Ahmadinejad said, thanking Obama for his willingness to enter direct talks with Iranians.

    The United States and other Western countries have reached a consensus on inviting Iran to direct talks over Iran's sensitive nuclear program.

    Iran, however, insisted that its nuclear program is only for peaceful purposes, and the debates over this issue is already over. Iran has vowed to continue its uranium enrichment activities and its potential talks with the West would be on management of the world instead of the nuclear issue.