The US envoy to six-party nuclear disarmament talks again ruled out any new incentives to draw North Korea back to the negotiating table as he arrived in South Korea Thursday .

Instead, US Assistant Secretary of State Christopher Hill urged the Stalinist state to stick to an agreement reached at the talks last September.

"It's not up to us to create some new incentive structures for them to come and implement the September agreement," he said as he arrived from China.

"The incentive structures are already in the September agreement."

In September, North Korea agreed to abandon its nuclear weapons program in return for security, diplomatic and energy aid guarantees.

But it boycotted the talks in November, protesting US financial sanctions on it for alleged money laundering and counterfeiting.

Hill, who is to meet his South Korean counterpart Chun Young-Woo and other officials during his two-day visit, said there was "no breakthrough" in efforts to lure North Korea back to the six-nation forum.

"I am not sure this is about US economic (sanctions). I think this is about a country, DPRK (Democratic People's Republic of Korea), that just has trouble making up its mind," he said.

North Korea has refused to return to the talks unless the United States lifts its sanctions.

Hill said a new peace mechanism could be discussed with the North in line with the agreement when the six-party talks resume.

"We are prepared to work on the implementation of all the elements of the September agreement, and you recall one of the elements there is that the parties agreed to work on a peace mechanism in an appropriate forum with appropriate players.

"So of course, we'll be prepared to implement that element as well."

In Beijing, Hill had said Washington would not offer North Korea any concessions to lure it back to negotiatiions.

"I don't think the agreement needs to be changed, I don't think the agreement needs to be sweetened," he said after talks with Vice Foreign Minister Wu Dawei.

"I think it is time the DPRK understands where their interests lie and come back to the talks," he said.