UNITED NATIONS - A month-long Review Conference on the Nuclear Non-Proliferation Treaty (NPT) began Monday with a predictable target: Israel.

A demonstrator holds a sign during an anti-nuclear weapons protest rally and march in New York May 3, 2010. REUTERS/Chip East As the only Middle Eastern country armed with nuclear weapons, Israel has been treated as a political sacred cow, one whose weapons programs have not been publicly challenged either by the United States or Western powers.

But on Monday an overwhelming majority of U.N. member states - 118 out of 192 - wanted the defiant Jewish state to come clean with its nuclear weapons program and sign the NPT, which is aimed at halting the spread of these devastating armaments.

Speaking on behalf of the 118-member Non-Aligned Movement (NAM), Indonesian Foreign Minister Marty Natalegawa said the fact that Israel has refused to sign and ratify the NPT has resulted in the continued exposure of non-nuclear weapon states of the region to nuclear threats by the only country possessing these weapons of mass destruction.

Israel, he warned, has also unleashed risks associated with the operation of "unsafeguarded nuclear facilities and activities of unknown safety standards".

Worse still, Israel has also implicitly triggered the threat of a nuclear arms race of "a catastrophic regional and international potential" thereby jeopardizing the NPT regime in its entirety, said Natalegawa, echoing the views of the largest single political coalition at the United Nations.

"This situation is unsustainable," as it also jeopardizes the implementation of the 1995 resolution calling for the creation of a nuclear-weapons-free zone (NWFZ) in the Middle East, Natalegawa warned.

The month-long conference, which runs through May 28, will take stock of the successes and failures of an international treaty aimed at halting the spread of nuclear weapons - and perhaps ultimately eliminating all nuclear weapons from the world's military arsenals.

The treaty, which was open for signature back in July 1968, has come under review every five years.

Today, 189 countries have acceded to the treaty, including the five declared nuclear powers, which are also the five permanent members of the U.N. Security Council: the United States, Britain, France, China and Russia.

The three undeclared nuclear powers are India, Pakistan and Israel, which are not parties to the NPT. North Korea acceded to the treaty, violated it, and later withdrew.

The 2000 NPT Review Conference reaffirmed the necessity of Israel's accession to the NPT, and the placement of all its nuclear facilities under comprehensive safeguards by the International Atomic Energy Agency (IAEA).

But so far, Israel has refused to accede to that request.

Speaking at the opening session Monday, U.N. Secretary-General Ban Ki-moon, who declared that disarmament and nuclear non-proliferation are among his "top priorities", singled out only two countries by name: Iran and North Korea.

He urged Tehran "to comply fully with Security Council resolutions and cooperate fully with the IAEA" and called upon North Korea to help achieve a "verifiable denuclearization of the Korean peninsula".

But he stopped short of making any references to Israel, India or Pakistan.

Still, he said, "I urge those countries that are currently outside the treaty regime to accede to it as soon as possible," without identifying the three countries by name.

Taking a righteous stand on nuclear weapons, Iranian President Mahmoud Ahmadinejad, the only head of state at the conference, said the sole function of nuclear weapons is to annihilate all living beings and destroy the environment.

The resulting radiation, he pointed out, would affect the coming generations and its negative impacts would continue for centuries.

"The nuclear bomb is a fire against humanity rather than a weapon for defence," he said.

"The possession of nuclear bombs is not a source of pride; it is rather disgusting and shameful," said Ahmadinejad, whose country is accused of trying to develop nuclear weapons: a charge he has flatly denied.

"And even more shameful is the threat to use or to use such weapons, which is not even comparable to any crime committed throughout the history," he declared.

Ahmadinejad did not spare Israel, accusing it of stockpiling hundreds of nuclear warheads. He accused the Jewish state of having waged many wars in the region and continuing to threaten the people and nations of the region "with terror and invasion".

But he also pointed out that Israel "enjoys the unconditional support of the U.S. government and its allies, and receives, as well, the necessary assistance to develop its nuclear weapons program".

He criticized the IAEA because it has failed both on nuclear disarmament and nuclear non-proliferation.

In response, U.S. Secretary of State Hillary Clinton charged that Iran was "do[ing] whatever it can to divert attention away from its own record and to attempt to evade accountability".

Tehran "has defied the Security Council and the IAEA and placed the future of the nonproliferation regime in jeopardy," Clinton said.

Meanwhile, at last month's nuclear security summit in Washington DC, U.S. President Barack Obama was asked about Israel's nuclear weapons program.

But he diplomatically sidestepped the question when he pointedly told reporters: "As far as Israel goes, I'm not going to comment on their (nuclear weapons) program".

"What I'm going to point to is the fact that consistently we have urged all countries to become members of the NPT. So there's no contradiction there," he said. "And so whether we're talking about Israel or any other country, we think that becoming part of the NPT is important."

"And that, by the way, is not a new position. That's been a consistent position of the United States government even prior to my administration," Obama added.