It is expected that the U.S. would take the lead among 10 nations yet to sign up to a global nuclear test ban treaty to take a significant step toward a goal of ridding the world of nuclear weapons.
U.N. Secretary-General Ban Ki-moon pushed for the 10 nations to sign up to the deal, saying it would ensure that North Korea's test blast last October is the world's final experiment with atomic weaponry.
Although 140 countries have ratified the treaty, the accord will not enter into force until it has been ratified by all 44 states listed in an annex that took part in a 1996 disarmament conference and have nuclear power or research reactors.
Only 34 of the 44 have done so. The 10 holdouts are China, Colombia, Egypt, India, Indonesia, Iran, Israel, North Korea, Pakistan and the U.S.
The Comprehensive Nuclear Test Ban Treaty, opened for signature in September 1996, bans all nuclear test explosions. Its aim is to eliminate nuclear weapons by constraining the development of new types of bomb.
The foreign ministers of Austria and Costa Rica, who are leading a two-day conference on the treaty in Vienna, told a news conference Tuesday that the pact was key to ridding the world of nuclear weaponry and called for U.S. leadership to seal the deal.
"The message from here in a way is, yes, we want U.S. leadership," Austrian foreign minister Ursula Plassnik told reporters.
Bruno Stagno Ugarte, Costa Rica's foreign minister, said the treaty was the "last possible barrier before the unthinkable" and urged the 10 countries to ratify the treaty as soon as possible.
Ugarte acknowledged that there had been "some reticence on behalf of the current U.S. administration" but added he hoped there would be movement on ratification.
"This is a pillar of the international confidence system," Ugarte said.
Ban Ki-moon relayed his message through an envoy Monday at the start of the two-day conference. On Oct. 9 last year, North Korea claimed to have tested a nuclear weapon.
Ban called the treaty "a major instrument in the field of disarmament and nonproliferation," and said if it came into force would help the larger goal of ridding the world of nuclear weaponry.
The conference is being attended by 103 countries, including seven of the ten not yet signed up. India, the U.S. and North Korea are not there.
Tibor Toth, executive secretary of the Vienna-based Comprehensive Nuclear Test-Ban Treaty Organization, called the coming period "defining" but appeared cautiously optimistic that the treaty would take effect.
"It is not just a dream - we are turning this dream into reality," Toth said.