Iranian President Mahmoud Ahmadinejad is on his way to New York City to take part in a conference on the Nuclear Non-Proliferation Treaty.

Mr. Ahmadinejad is due to address delegates Monday on the first day of the month-long conference at U.N. headquarters. He is expected to defend Iran's right to enrich uranium, and to propose changes to the treaty.

Before leaving Tehran for New York, Mr. Ahmadinejad criticized the production and stockpiling of nuclear weapons.

Iran is a signatory to the Nuclear Non-Proliferation Treaty, which is designed to check the spread of atomic weapons worldwide.

However, the United States accuses Iran of secretly working to produce a nuclear weapon. The U.S. and its allies are seeking a fourth set of U.N. sanctions to pressure Iran to stop enriching uranium.

Iran says its enrichment program is for peaceful purposes.

U.S. Secretary of State Hillary Clinton is also scheduled to address the conference on Monday.

The review conference of states that are party to the Nuclear Non-Proliferation Treaty has been held every five years since the treaty went into effect in 1970.