Seoul  - US President Barack Obama said Thursday that the international community's patience in the nuclear disputes with Iran and North Korea was running out.

Neither Iran nor North Korea could continue to bank on the world community continuing to accept endless talks and negotiations which lead to no results, without taking any action, Obama said after a meeting with his South Korean counterpart Lee Myung Bak.

Much to Washington's disappointment, there has been no positive reaction from Tehran to the international community's "fair offer," Obama said, adding that Iran must be given a "clear message."

"Our expectations are that over the next several weeks we will be developing a package of potential steps that we could take that will indicate our seriousness to Iran," he said.

Iran's Foreign Minister Manouchehr Mottaki said Wednesday that Iran was rejecting a deal negotiated by the International Atomic Energy Agency under which Iran was supposed to ship its low-grade enriched uranium to Russia and France where it would be processed into fuel for Tehran's medical research reactor.

Obama and Lee also urged North Korea to return to nuclear talks.

Obama said he planned to send his special envoy to North Korea on December 8 in a bid to restart stalled multinational talks.

Speaking at a press conference in Seoul on the final leg of his Asian tour, Obama said the trip by Stephen Bosworth, the US special representative for North Korea policy, should help revive the six-party talks, which North Korea abandoned in April.

China, South Korea, Russia and Japan also participate in the talks.

The two leaders reaffirmed their unity in approaching the North Korea issue, saying they were seeking to break the pattern where Pyongyang first ratchets up tension, then agrees to talks only to break them off again.

"The thing I want to emphasize is that President Lee and I both agree that we want to break the pattern that existed in the past, in which North Korea behaves in a provocative fashion, and then is willing to return to talks ... and then that leads to seeking further concessions," Obama said.

Lee again mooted a "grand bargain" solution, in which Pyongyang would shut down its nuclear programme for good in return for substantial aid.

"I hope that by accepting our proposal, the North will secure safety for itself, improve the quality of life for its people and open the path to a new future," the South Korean president said.

Other subjects for discussion were the US-South Korean security alliance and the planned ratification of a free-trade deal.

Obama and Lee stressed that bilateral relations had never been better than now. The US would never waver in its obligations to aid South Korea, Obama later told soldiers at a US military base near Seoul, the Yonhap news agency said.

About 28,500 US soldiers are currently deployed in South Korea as a deterrent to North Korea.

On his first Asian tour Obama has already visited Japan, Singapore, where he attended the Asia-Pacific Economic Cooperation summit, and China. (dpa)