The U.N. Secretary-General and Security Council should take on the job of blocking the spread of nuclear weapons if the troubled conference on the nonproliferation treaty fails to take action, former U.S. Defense Secretary Robert S. McNamara said Tuesday.

"There's a high probability - I would say a certainty - that the conference will fail," said McNamara, who once oversaw 30,000 nuclear warheads but has since become a leading voice for disarmament.

A chief German delegate endorsed McNamara's proposal and a key committee chairman signaled the month-long conference might, indeed, fail to produce major agreements.

The diplomats and advocates met with reporters as the conference to review the 1970 Nuclear Nonproliferation Treaty entered its final four days with wide gaps still separating the more than 180 treaty nations, particularly over whether speedier cuts in U.S. and other nuclear arsenals should get equal attention with the nuclear confrontations involving Iran and North Korea.

The agenda dispute delayed the nuts-and-bolts work of conference committees for almost three weeks, leaving little time for substantive negotiation.

Under the treaty, nations without nuclear weapons are committed not to pursue them, in exchange for a pledge by five with the weapons - the United States, Russia, Britain, France and China - to move toward eliminating their arsenals. The non-weapons states, meanwhile, are guaranteed access to peaceful nuclear technology.

Iran cites that guarantee in justifying its uranium-enrichment program, which can produce both fuel for peaceful nuclear energy and material for bombs. European diplomats resume negotiations with Tehran on Wednesday in an effort to get the Iranians to roll back the program.

Some here had hoped the treaty review, held every five years, might address the Iran situation by setting new rules for access to such sensitive dual-use technology. The issue's complexity makes any concrete steps unlikely, however, in the short time left.

Less unlikely is a conference position on North Korea. The first "defector" from the treaty, North Korea announced its withdrawal in 2003 and now claims to have built nuclear weapons - all done without consequences under the treaty. Many want to make it harder to exit the treaty, and to threaten sanctions against those who do.

The review logjam has stirred talk of other ways to achieve the treaty's goals. The Bush administration, often wary of multilateral agreements, is touting its Proliferation Security Initiative - one-on-one agreements with other nations to intercept illicit nuclear trade. Some disarmament groups, for their part, favor a possible World Court lawsuit to pressure the nuclear powers toward disarmament.

The 88-year-old McNamara focused on a role for the 15-nation U.N. Security Council.

The former World Bank president and U.S. defense chief in 1961-68, said the Iran and North Korea situations pose a great danger to world security, especially because "if both countries continue their present programs, other nations will follow." He mentioned Japan and South Korea in east Asia, and Egypt and Saudi Arabia in the Middle East as potential "copycats."

"If the conference fails (to deal with Iran and North Korea), as I predict it will, I think the Security Council and secretary-general should assume responsibility," McNamara said.

He said that as nuclear risks increase, U.N. chief Kofi Annan should recommend Security Council actions to deal with them. The council has the power to impose economic sanctions, for example, or even authorize military force.

Appearing with McNamara, Friedrich Groening, a chief German conference delegate, noted that the European Union also favors a stronger Security Council role as "final arbiter" on nonproliferation treaty violations. He said a "strategic consensus" would be needed, an allusion to divergent views among the United States and other major powers that often paralyze Security Council action.

Past efforts to bring the North Korean situation before the council, for example, have been blocked by China.

As the treaty review struggled into its final days, Swedish Ambassador Elisabet Borsiin-Bonnier, head of a main committee, signaled it was unlikely to produce written accords on major issues.

"Some of these issues, if you sit another week, we might not solve these issues," she told reporters. "Irrespective of what comes out on a piece of paper, these discussions have helped us focus on difficult issues."