Weeks-long U.N. nuclear summit begins

UNITED NATIONS, May 3 (UPI) -- U.S. President Barack Obama Monday warned Iran against pursuing nuclear weapons development as a U.N. conference on non-proliferation got under way.

"Nations that ignore their obligations find themselves less secure, less prosperous and more isolated," Obama said in a statement as Iranian President Mahmoud Ahmadinejad characterized the United States as a rogue nation in remarks to the U.N. Nuclear Non-Proliferation Treaty Review Conference.

"For four decades, the (treaty) has been the cornerstone of our collective efforts to prevent the proliferation of these weapons. But today, this regime is under increasing pressure," Obama said, adding nations have an obligation to work together for a more secure world.

Earlier, Ahmadinejad called the possession of nuclear weapons "disgusting and shameful," and said threatening to use them was even worse.

The Iranian leader's presence at the United Nations sparked calls from a New York lawmaker for his arrest for inciting genocide by threatening to destroy Israel.

U.N. Secretary General Ban Ki-moon told the conference it is up to Iran to convince the world its intentions are peaceful to avoid sanctions.

The U.N.-sponsored conference is conducted every five years to review the treaty.

Iran denies it is building a bomb, saying its nuclear program is for peaceful purposes. But the International Atomic Energy Agency censured Tehran last year for secretly building a nuclear facility and defying U.N. resolutions on uranium enrichment.

Two agendas likely will be in play during the conference, U.S. administration advisers told The New York Times. The Obama administration is trying to induce Middle Eastern countries to keep away from enriching uranium for reactor fuel then later searching for spent fuel for plutonium, a treaty loophole that has allowed Iran to creep toward the capability of manufacturing nuclear weapons, the Times said.

While most advisers and diplomats agree the loophole won't be closed during the conference, they said White House officials could work to persuade countries in the region from building nuclear reactors able to produce an atomic device out of fear of Iran's nuclear capabilities, the report said.

Meanwhile, Iran and other nations attending the U.N. conference said they want to force Israel, the Middle East's only nuclear weapons state, to acknowledge its arsenal and sign the non-proliferation pact.