Updated

UNITED NATIONS (AP) — The U.S. and others warned Friday of a possible ultimatum in Geneva: Either the Conference on Disarmament gets moving on a treaty to ban production of atomic bomb material, or big players will take their bargaining chips elsewhere.

The warning was aimed at Pakistan, the latest nation to block negotiation of a Fissile Material Cutoff Treaty at the 65-nation disarmament conference in that Swiss city, a diplomatic forum where just one delegation can prevent the required consensus.

"It strikes us as unwarranted for a single country to abuse the consensus principle and thereby frustrate everyone else's desire to resume disarmament efforts," said White House arms-control chief Gary Samore.

The U.S. itself until last year was blocking the same long-proposed treaty, and some countries Friday complained that Western nations also bear blame for the Geneva standoff.

They should not limit the disarmament body's focus to one treaty, but should also be negotiating pacts to prevent an arms race in outer space, to forswear nuclear attacks on non-nuclear states, and to ban nuclear weapons outright, said Egypt's U.N. Ambassador Maged Abdelaziz.

The conference should "agree by consensus on a balanced and comprehensive program of work," Abdelaziz said on behalf of the 118-nation Nonaligned Movement of mostly developing countries.

Samore, Abdelaziz and more than 60 other top envoys, including foreign ministers, spoke at a high-level meeting convened by U.N. Secretary-General Ban Ki-moon to rally support for action at the Geneva conference, which Samore said must be awakened "from its many years of slumber."

The Conference on Disarmament, the world's only multilateral forum for nuclear arms diplomacy, hasn't produced anything substantial since the 1996 nuclear test-ban treaty, a pact now on hold because key nations, including the U.S., have not ratified it.

The fear that terrorists might get hold of plutonium or highly enriched uranium — nuclear bomb-making material — has added to the push for a fissile-material treaty. Experts believe 2,500 tons of the stuff sit today in deployed or disused weapon warheads, in fuel stores for nuclear-powered Russian icebreakers and U.S. missile submarines, in research reactors and elsewhere.

The U.S. administration of President George W. Bush had opposed negotiating a cutoff pact, arguing it would not be verifiable because the inspection regime would be too objectionably intrusive.

President Barack Obama reversed that stand last year, and the Geneva conference finally agreed on an agenda. Pakistan allowed the process to move forward, but this year it blocked further work.

At this time only Pakistan and India — and possibly Israel and North Korea — produce fissile material for weapons. The major nuclear powers, with thousands of weapons stockpiled, have declared unilateral moratoriums on production.

Archrival India has more fissile material than Pakistan does, and a greater capacity to build warheads. The Islamabad government consequently wants a treaty that doesn't only cut off future production, but reduces current stocks of bomb material.

"It presents us with a clear and present danger," Pakistan's Geneva negotiator, Zamir Akram, has said of the cutoff idea.

The Pakistanis didn't speak at Friday's session, and spokesman Mian Jahangir Iqbal said the U.N. mission would have no comment.

The U.S., Australian, British and other speakers suggested the negotiation of a fissile material treaty might have to be shifted elsewhere, perhaps to the U.N. General Assembly, where it can be adopted by majority vote. Rejectionists would then become more internationally isolated.

"Mexico feels the time has come to issue an ultimatum," agreed Mexican U.N. Ambassador Claude Heller.

But Russia and China, influential voices as nuclear-weapon states, opposed the idea.

Disarmament expert Ray Acheson, of the advocacy group Reaching Critical Will, told The Associated Press it might prove "reasonable" to shift to the General Assembly, though unfortunate to exclude Pakistan. The best solution, Acheson argued, would be to leapfrog such intermediate problems by negotiating a treaty outlawing nuclear weapons.

Secretary-General Ban said he would ask his disarmament advisory group to study the issue.