UNITED NATIONS - Iran and Egypt are gearing up for battle against the United States and its allies over Israel and developing countries' rights to atomic technology at a major meeting on the Non-Proliferation Treaty. Iranian President Mahmoud Ahmadinejad is expected to attend the conference, which opens on Monday and runs until May 28. He will be facing off with Secretary of State Hillary Clinton, who heads the US delegation at the meeting at UN headquarters. Diplomats expect Ahmadinejad to take a defiant stand against the United States and its Western allies, accusing them of trying to deprive developing states of nuclear technology while turning a blind eye toward Israel's nuclear capability. The 189 signatories of the landmark 1970 arms control treaty - which is intended to stop the spread of nuclear weapons and calls on those with atomic warheads to abandon them - gather every five years to assess compliance with the pact and progress made toward achieving its goals. The last NPT review conference in 2005 was widely considered a disaster. After weeks of procedural bickering led by the former US administration, Egypt and Iran, the meeting ended with no agreement on a final declaration. Analysts and UN diplomats hope things will be different this time and that the conference can breathe new life into a treaty that has failed to prevent North Korea from building a nuclear bomb or force Iran to stop uranium enrichment. A Pakistani-led illicit nuclear supply network and slow progress on disarmament have also highlighted the NPT's weaknesses. Israel is presumed to have a nuclear arsenal but neither confirms nor denies having one. Like India and Pakistan, it has not signed the NPT and will not participate in the conference. Ahmadinejad is the highest-ranking official attending the conference. He will travel to New York as diplomats from the five permanent UN Security Council members and Germany are meeting nearly every day in Manhattan to hammer out a draft resolution imposing a fourth round of sanctions against Tehran over its nuclear programme.