North Korea could conduct a third nuclear test or another missile launch before next year's US and South Korean presidential elections if disarmament talks fail, a senior Seoul official warned on Friday.

The communist North abandoned six-party nuclear talks in April 2009 and staged its second nuclear test a month later. It now calls for an unconditional resumption of the negotiations, amid tentative signs of tensions easing.

But Kim Tae-Hyo, presidential secretary for national security strategy in Seoul, said another North Korean nuclear test or a long-range missile launch was possible if talks are not successful.

"North Korea could take provocative acts if it judges it won't be able to extract economic aid from South Korea and the US ahead of next year's presidential elections in both countries," Kim told a security forum.

Chun Yung-Woo, senior presidential security secretary, told the same forum the North must shut down its newly disclosed uranium enrichment programme before the six-nation nuclear talks can restart.

"In order for the six-party talks to resume, North Korea must show sincerity and take the required pre-steps, including a monitored shutdown of its uranium enrichment programme," Yonhap news agency quoted him as saying.

"North Korea claims that the six-party talks should be resumed without preconditions but it does not want to tackle the core issue -- nuclear weapons," Chun said.

The United States and South Korea say before talks can begin Pyongyang must show it is serious about the process, notably by shutting down the uranium programme which could be reconfigured to make bombs.

"As a matter of principle, we have no intention of rewarding North Korea for its illegal nuclear weapons," Chun said.

Last month, the nuclear envoys of South and North Korea held their second meeting in as many months to try to lay the groundwork for the resumption of the six-party talks. No significant progress was reported.

US and North Korean officials met separately in New York in late July, and there are media reports that another meeting is planned. The forum also includes China, Russia and Japan.

US Assistant Secretary of State Kurt Campbell said in Seoul that no decision has been taken about possible next steps.

US President Barack Obama and South Korean President Lee Myung-Bak will discuss the "appropriate way forward" at their summit on October 13 in Washington, Campbell said.

He was speaking after talks with Foreign Minister Kim Sung-Hwan to discuss the two countries' joint approach to North Korea.

N.Korea must shut uranium programme for talks: Seoul
Seoul (AFP) Oct 7, 2011 - North Korea must shut down its newest nuclear programme before long-stalled six-nation disarmament talks can resume, Seoul's top presidential security aide said Friday.

Chun Yung-Woo, senior secretary for foreign affairs and national security, said other parties in the talks would not reward the North for abandoning its "illegal" nuclear activities.

"In order for the six-party talks to resume, North Korea must show sincerity and take the required pre-steps, including a monitored shutdown of its uranium enrichment programme," he told a security forum.

"North Korea claims that the six-party talks should be resumed without preconditions but it does not want to tackle the core issue -- nuclear weapons," Chun said.

The North abandoned the six-party forum in April 2009 and staged its second nuclear test a month later. It now calls for an unconditional resumption of negotiations.

But the United States and South Korea say the North must first show it is serious about the process, notably by shutting down the uranium enrichment programme which could be reconfigured to make bombs.

"As a matter of principle, we have no intention to reward North Korea for its illegal nuclear weapons," Chun said.

Last month, the nuclear envoys of South and North Korea held a second meeting in as many months to try to lay the groundwork for the resumption of the six-party talks. No significant progress was reported.

US and North Korean officials met separately in New York in late July, and there are media reports that another meeting is planned. The forum also includes China, Russia and Japan.

Chun denied the conservative South Korean government, which rolled back the previous liberal government's policy of engagement and reconciliation, was seeking to push the North's regime towards implosion.

"When we pursue reunification as a policy, we don't seek the North's collapse," he said, adding that the goal was to induce reform and openness.

Seoul and Washington are coordinating their stance on the six-party talks before next week's summit in Washington between the US and South Korean presidents.

US Assistant Secretary of State Kurt Campbell will meet Foreign Minister Kim Sung-Hwan in Seoul later Friday.