The Obama [Images] administration has said that North Korea should give up its ambition of becoming a nuclear power before returning to the denuclearisation talks.

"The North Koreans are well aware of what they need to do to come back to the six-party talks in dealing with this issue, and that is give up the idea of a nuclear state on the peninsula, just as it agreed to do several years ago," White House spokesman Robert Gibbs said.

"If they are willing to live up to those obligations, then we will make progress in those talks. But this isn't a step for us to take. This is a step for the North Koreans to take in living up to those obligations," Gibbs said.

The White House spokesman said the way to have the most constructive talks for North Koreans is to come back to the table and live up to the obligations that they agreed to and then walked away from.

Earlier, the North Korean media reported that Pyongyang will not be attending six-party talks unless the United States agrees to peace treaty with it.

In reply, US Assistant Secretary of State for Public Affairs P J Crowley said if North Korea says yes and comes back to the six-party process, if it makes affirmative steps toward denuclearisation, then a wide range of other opportunities open up for them.

"But North Korea has to come back to us, say yes, come back to the six-party process, start working on it's obligations under the joint statement. And then we are perfectly willing to have other kinds of discussions," Crowley said.

"We want to see North Korea come back to the six-party process. Remember, if you want to have a negotiation regarding an armistice, we are not the only party, you know, to that prospective negotiation. So that's expressly why we think having a multilateral process like the six-party process is important," he said.

"So right now, the issue before North Korea is saying yes, coming back to the six-party process, and then we can begin to march down the list of issues that we have, beginning with the nuclear issue," Crowley said.

The Obama administration also ruled out lifting of the sanctions against North Korea.

"We've made clear, going back several months, we are not going to pay North Korea for coming back to the six-party process," he said.

"We want to see denuclearisation in North Korea. We want to see North Korea move down a different path, integrate itself into the region, become a more constructive player. But we also want to see North Korea improve its dreadful human rights record," Crowley said.

"That is expressly the reason why we have an envoy. He's in the region. He's making it clear to North Korea that we place great attention on this human rights agenda, and we'll continue to press them to improve their performance," he said.