The U.S. State Department on Friday formally announced that a planned meeting on establishing the Middle East as a WMD-free zone would not occur this year, Reuters reported.
There had already been little optimism that the event would occur as hoped next month in Helsinki, Finland.
"As a co-sponsor of the proposed conference ... the United States regrets to announce that the conference cannot be convened because of present conditions in the Middle East and the fact that states in the region have not reached agreement on acceptable conditions for a conference," according to State Department spokeswoman Victoria Nuland.
She added in prepared comments that "a deep conceptual gap persists in the region" on security and arms control matters, and that "outside states cannot impose a process on the region any more than they can dictate an outcome."
Nuland offered no concrete indications on whether the summit would be convened at a later date.
Nations participating in the 2010 Nuclear Nonproliferation Treaty review conference called for the WMD-free zone conference to be held this year. Russia, the United Kingdom and the United States were the primary sponsors of the anticipated gathering, with Finnish diplomat Jaakko Laajava designated as its "facilitator."
Washington has worried that the meeting might offer Arab states a high-profile opportunity to criticize Israel, which is widely believed to hold the region's sole nuclear arsenal. Israel had not officially said whether it would attend, but longtime foe Iran had said it would send a delegation.
"We would not support a conference in which any regional state would be subject to pressure or isolation," Nuland said.
Washington and Tel Aviv have said that any regional WMD-free zone would be dependent on resolution of the Arab-Israeli conflict, which flared again this month in Gaza, and addressing concerns that Iran's nuclear program is aimed at giving that nation a weapons capability.
Nuland said the State Department intended to press ahead with efforts to make the conference a reality.
"The United States will continue to work with our partners to support an outcome in which states in the region approach this issue on the basis of mutual respect and understanding and with acknowledgement of the challenges inherent in advancing regional security and arms control," she said. "A conference handled this way, with direct engagement of the regional states, will enjoy the greatest prospects for success."
The United Kingdom and United Nations on Saturday said the meeting could occur in 2013, Reuters reported.
"We support the convening of a conference as soon as possible. We endorse fully the work of the conference facilitator, Finnish Undersecretary of State Jaakko Laajava, to build consensus on the next steps," according to British Foreign Office Minister Alistair Burt.
"We welcome his commitment to conduct further multilateral consultations with the countries of the region to agree arrangements for a conference in 2013," he added.
U.N. Secretary General Ban Ki-moon said he would look for the event to occur at "the earliest opportunity" in 2013.
"I reaffirm my firm resolve and commitment together with the Russian Federation, the United Kingdom and the United States, in consultation with the states of the region, to convene a conference," Ban stated in prepared comments.
Laajava said he intended to call that talks between interested nations "be held as soon as possible."
Iran on Monday said failure to convene the meeting "is a serious setback to the NPT and this is a clear sign that the U.S. is not committed to the obligation of a world free of nuclear weapons," Reuters reported.
"The U.S. has taken hostage this Helsinki conference for the sake of Israel ... they want to support the Israelis' nuclear weapon capability," said Ali Asghar Soltanieh, Tehran's ambassador to the International Atomic Energy Agency.
There is some suspicion among envoys from Western nations that Iran accepted the invitation to the conference because it had determined the meeting was not going to occur this year, according to Reuters.
Arab League head Nabil Elaraby said the delay would "have a negative impact on regional security and the international system to prevent nuclear proliferation as a whole," Reuters reported.