The United States has proposed a meeting of North Korea's neighbors and other regional powers on the sidelines of the upcoming meeting of the UN General Assembly, South Korea's top nuclear envoy said. If realized, such a meeting could put further pressure on North Korea, which has refused to rejoin six-party talks aimed at ending its pursuit of nuclear weapons. US Assistant Secretary of State Christopher Hill, however, stressed that such talks would not undermine the six-party negotiations. The move comes amid concerns the North may be preparing to test a nuclear bomb, escalating tensions already high after Pyongyang test-fired a series of missiles in July. Chun Yung-woo, the chief South Korea nuclear negotiator, said on Monday the US-proposed session would be similar to one in Kuala Lumpur, Malaysia on the sidelines of an annual security forum in July. That session included all parties to the six-nation nuclear talks except North Korea - China, Japan, South Korea, Russia and the US - plus Australia, Malaysia, Indonesia, Canada and New Zealand. "For now, the US is thinking of holding a meeting similar to the one held in Kuala Lumpur," Chun said after talks with Hill. "But not all of the related countries have responded," he said without naming them. North Korea has refused to attend the six-party talks since November in anger at US financial santions over its alleged currency counterfeiting. Concerns have persisted in recent weeks that North Korea may be preparing to conduct its first known nuclear test following reports last month of suspicious activity at a suspected North Korean underground nuclear testing site. South Korea's main spy agency has said the communist regime could test a nuclear device at any time, and on Monday, South Korean Defense Minister Yoon Kwang-ung told a parliamentary meeting that a nuclear test by the North remains a possibility. He didn't elaborate. Many experts believe the North has enough radioactive material to build at least a half-dozen or more nuclear weapons. Such fears, coupled with tensions in the wake of the North's missile launches in July, have inspired fresh calls for resuming six-nation talks. Hill, who arrived in Seoul on Monday, said he discussed with Chun having "various talks" now that the six-nation negotiations have been deadlocked for almost a year. He said the US is prepared to discuss the financial restrictions if Pyongyang returns to the negotiating table and moves toward implementing a September 2005 agreement where it promised to abandon its nuclear program in exchange for aid and security guarantees.