UN atomic agency chief Yukiya Amano has not been able to narrow Israeli-Arab differences on how to move towards a Middle East free of nuclear weapons, but will keep trying, according to a report by his office.
Discussions with officials from the region have shown that there continues to be a "fundamental difference of views" between Israel and the other Middle East countries, it said.
The report was prepared by Amano's International Atomic Energy Agency ahead of an annual meeting next month of the IAEA's 159 member states.
Israel is widely believed to possess the Middle East's only nuclear arsenal, drawing frequent Arab and Iranian condemnation. It is the only country in the region outside the global nuclear Non-Proliferation Treaty (NPT).
Israel and the United States regard Iran as the world's main proliferation threat, accusing it of covertly seeking a nuclear arms capability, something the Islamic state denies.
An Egyptian plan for an international meeting to lay the groundwork for creating a Middle East free of weapons of mass destruction - including nuclear arms - was agreed at an NPT review conference in 2010.
But the United States, a co-sponsor along with Britain and Russia, said last year that the conference would not occur as planned in December 2012, and did not make clear when, or whether, it would take place.
US and Israeli officials have said a nuclear arms-free Middle East cannot become reality unless there is broad Arab-Israeli peace and Iran curbs its nuclear programme.
As in previous years, the IAEA's 2012 meeting asked Amano to hold consultations with Middle East states on placing all nuclear activities there under the supervision of the agency.
Amano's report ahead of this year's member state gathering, dated 16 August, said he had encouraged the development of "relevant new ideas and approaches".
Despite this, he had not been able to make further progress on the application of "comprehensive Agency safeguards covering all nuclear activities in the region of the Middle East" it said, adding that he would continue with his consultations.