UN Secretary-General Ban Ki-moon urged nations to seize on recent momentum in nuclear disarmament talks, saying they had a historic opportunity to make the world a safer place. Closer cooperation between the United States and Russia this year has focused attention on negotiations at the 65-nation nuclear disarmament body. "Now is the time to break more than 10 years of stalemate," Ban told the Conference on Disarmament on Tuesday, calling for more intensive efforts to reduce the number of atomic weapons and ban production of the key ingredient for making them. Ban referred to "new initiatives from nuclear and non-nuclear states that together provide a new momentum for disarmament." But he said he was particularly encouraged by Russian and US pledges to hammer out a successor treaty to the 1991 START I accord cutting US and Russian nuclear arsenals. On Tuesday, the two sides launched talks in Moscow to make proposals for a new agreement before President Barack Obama visits in July. The current accord expires in December. The Conference on Disarmament has failed to produce anything of substance since the 1996 Comprehensive Nuclear-Test-Ban Treaty. Confidence in the UN body was shattered during George W. Bush's presidency, when the United States withdrew from the 1972 Anti-Ballistic Missile Treaty and from six years of talks on a biological weapons ban. But diplomats in Geneva credited Obama with giving new life to the talks by signaling an end to American objections over inspections and monitoring of disarmament treaties. In a speech last month, Obama said his agenda included a "new treaty that verifiably ends the production of fissile materials intended for use in state nuclear weapons." The key word was "verifiable," signaling a shift from the Bush administration's objection to global inspections and monitoring systems as too costly, less than foolproof and possibly intrusive on military and industrial secrets. Ban said provisions for "international and effective verification" of a treaty demanding countries halt production of the fissile material needed for making atomic bombs was "an important step forward." He said he was heartened the conference was meeting in "an improved international climate." "You have an opportunity to build on advances already made, leave behind entrenched positions and look instead to shared aims of peace and development," Ban told the conference. "Business as usual should not prevail." The secretary-general urged multilateral efforts to fulfill a five-point plan he released in October, including talks both to eliminate nuclear weapons and to reassure non-nuclear nations they will not be attacked by those possessing atomic bombs. He also said it was of "crucial importance" that the nuclear weapons test ban enters into force. The treaty still requires signatures from India, Pakistan and North Korea, and the ratification of China, Egypt, Indonesia, Iran, Israel and the United States. Obama is expected to ask the US Senate to seal Washington's ratification. The Senate rejected the deal during Bill Clinton's presidency. Ban made only brief mention of a proposal from China and Russia to prevent "an arms race in outer space," which the US has warmed to after long labeling it a ploy to gain military advantage.