A landmark UN conference on fighting the spread of nuclear weapons headed into its final week Monday with eyes on Iran�s efforts to avoid fresh UN sanctions against its atomic program.

Iran is seen as a test case for the 189-nation Non-Proliferation Treaty (NPT) as it claims its nuclear work is peaceful but is under three rounds of UN sanctions to get it to rein in its atomic work over fears it seeks the bomb.

The NPT conference here was still struggling to revise a draft final statement, three weeks after opening on May 3.

Committees were meeting Monday on the three pillars of the NPT -- disarmament, monitoring nuclear programs worldwide to make sure they are not used to make weapons, and promoting the peaceful use of nuclear energy.

Conference President Libran Cabactulan of the Philippines has set a deadline of Monday to turn the committee proposals into a draft final statement. The conference is to begin a last run of plenary sessions on Tuesday.

In an effort to show good faith and avoid new sanctions, Iran struck a last-minute deal with Brazil and Turkey last week on a nuclear fuel swap.

In Vienna Monday, Iran formally notified the UN watchdog International Atomic Energy Agency of this deal.

The IAEA said it would pass on the letter to the United States, France and Russia -- which had offered to supply much-needed fuel to a research reactor in Tehran under a UN-brokered deal last October.

The bargain is for Iran to ship most of its low-enriched uranium (LEU) out of the country in return for higher grade reactor fuel to be supplied by Russia and France.

But Iran stalled on the deal, insisting it wants a simultaneous swap on its own soil, which was rejected by world powers.

Tehran now has promised to deposit 1,200 kilograms (2,640 pounds) of LEU in Turkey in return for the reactor fuel.

Western governments' reaction has been dismissive as they say Iran is still failing to address international concerns about its nuclear program.

Washington has pressed ahead at the UN Security Council by circulating a new sanctions resolution.

But officials close to the UN talks said reaching a decision on sanctions was on hold until the status of the fuel swap is cleared up.

The to-and-fro over Iran has dominated the conference, even if US President Barack Obama�s moves towards disarmament, such as a new strategic weapons agreement with Russia, have given Washington increased credibility.

Non-proliferation analyst Rebecca Johnson said "the review conference has a real chance of being able to adopt a constructively useful (if not fabulously forward-looking) outcome."

Sticking points include whether to set a deadline for disarmament, something nuclear weapons state resist and which is almost certain not to be in any final document.

Another thorny matter is an Egyptian-led proposal to set up a nuclear weapons-free zone in the Middle East.

US and Egyptian officials have been meeting on this for almost two months and will be seeking a compromise in New York that would allow Israel to take part.

Israel is not against such a zone but says it can only come after a peace agreement for the region.

Egypt is promoting the zone, however, as a way to move towards peace, especially since Israel is allegedly the only nuclear weapons state in the Middle East.

Other major areas of dispute at the NPT conference are whether to make tougher nuclear inspections mandatory for all member states and how to penalize states, such as North Korea, which withdraw from the treaty in order to make the bomb.

The NPT, which went into effect in 1970, is in crisis, with questions about how to monitor suspicious nuclear programs in Iran and North Korea and how to get nuclear-weapon states to carry out their treaty promise to move towards disarmament.

The previous NPT review failed in 2005 to reach agreement but the atmosphere has been better this time around in the twice-a-decade meetings.