Iranian President Mahmoud Ahmadinejad called for the United States to be suspended from the International Atomic Energy Agency.
The Iranian leader opened a two-day nuclear conference in Tehran Saturday, just days after the U.S. held a similar summit in Washington and pointedly did not invite Iran.
Mr. Ahmadinejad launched a broad attack on the world's nuclear monitors, slamming the structure of the U.N. atomic agency, the U.N. Security Council, and the Nuclear Non-Proliferation Treaty, or NPT.
He said nuclear armed countries, in particular the United States, should not be part of the IAEA. That would also include Iran's most powerful backers on the nuclear issue - China and Russia - though their support has been recently wavering.
As an alternative to the current structure of nuclear oversight, the Iranian leader proposed an "independent" international group to monitor nuclear disarmament and stem proliferation.
In that vein, Mr. Ahmadinejad called for a review of the NPT, saying non-nuclear weapon states should revise the treaty. He argued that the U.S. and other nuclear-armed nations would hamper a "just commitment."
Strengthening the NPT was one of the goals of the Washington conference. The U.S. and others say Iran is not living up to its obligations under the treaty, to which it is a signatory. At issue is Tehran's secrecy concerning its nuclear program, which it says is for civilian purposes. Western nations, among others, suspect it is aimed at building nuclear weapons.
In Tehran, delegations from Syria, Lebanon and Iraq voiced their support for Iranian nuclear activities, which they described as peaceful.
Iranian media report they also called for Israel to join the non-proliferation pact. Israel is widely believed to have the only nuclear arsenal in the Middle East, but neither confirms nor denies its existence.
Mr. Ahmadinejad also called the veto power wielded by the permanent members of the U.N. Security Council unjust. He suggested if it must continue, it should be held by countries from Latin America and other traditionally unrepresented nations.
Iranian media reported envoys from some 60 nations and several international and non-governmental groups are attending the conference, which is being held under the banner of "nuclear energy for all, nuclear weapons for no one."
It appeared timed to counter the U.S. meeting and question America's right to lead the nuclear discussion. President Barack Obama used the Washington summit to press for a fourth round of U.N. sanctions against Tehran. Iranian leaders also objected strongly to the recent revision of U.S. policy which reserves the right to strike Iran and North Korea.
President Ahmedinejad, whose government has issued a series of contradictory messages about its nuclear program, Saturday condemned nuclear arms in general, arguing reliance on such weapons in global affairs is a legacy of "uncultured and backward governments."