Korea, the United States and Japan on Monday warned that North Korea will risk facing more sanctions and deepening its isolation if it conducts a nuclear test, imploring the North to take a "different path" to refrain from further provocations.

The united message came after high-level diplomats from the three nations held three-way talks in Seoul earlier in the day to discuss ways to curb further provocations by North Korea amid concerns it may be preparing to proceed with a third nuclear test.

The talks involved Lim Sung-nam, Seoul's chief nuclear envoy, his Japanese counterpart Shinsuke Sugiyama, and Glyn Davies, the U.S. special envoy for North Korea policy.

"I think it would be a serious miscalculation and mistake if North Korea worked to engage in a nuclear test," Davies told reporters after the Monday talks.

"If there is further provocation such as a nuclear test, there will be swift and sure reaction by the international community," Davies said.

Concerns have grown after its failed launch of a long-range rocket on April 13, a clear violation of U.N. resolutions that prompted the international community to tighten sanctions against the impoverished regime.

Asked about whether there are any imminent signs of a nuclear test in North Korea, Davies replied, "I don't have any particular word to convey to you about that. We all have followed the same information that you've seen about what may or may not be going on in North Korea to prepare for a nuclear test."

"We are united in our resolve, to respond not just (as) the three allies, but Russia and China as well," Davies said, adding he hopes that North Korea does not "miscalculate" and will make "a different set of decisions."

Earlier in the day, the South Korean envoy Lim also called on North Korea's new leadership to take a "different path" toward peace and change its course of provocations.

"In response to the failed launch, the international community, including the three of us, as well as China and Russia, has been able to send a clear and consistent message to Pyongyang that North Korea should refrain from any further provocations," Lim said in his opening remarks.

"There will be a different path for them if they make the right decision," Lim said, adding he hopes that the Monday talks could "lead North Korea to the right side of peace."

In a separate meeting with the media after the talks, Sugiyama also echoed the remarks by Lim and Davies.

If North Korea proceeds with a "further escalation" of tensions on the Korean Peninsula, the three nations will take a "unified and coordinated action," Sugiyama said.

"If, otherwise, DPRK (North Korea) decides rightly, all of our three are ready to go for a different path," Sugiyama said.

Seoul officials said that the Monday talks were aimed at assessing the situation on the Korean Peninsula following the failed launch of a long-range missile and discussing ways to prevent North Korea from carrying out additional provocations.

Davies will leave for Beijing on Tuesday where he plans to meet with Wu Dawei, China's chief nuclear envoy on North Korea, the official said.

With the defiant launch last month, North Korea reneged on a Feb. 29 deal with the U.S. that had spawned some hope of diplomacy with the North under new leader Kim Jong-un, who inherited the impoverished state following the death of his father Kim Jong-il in December.

Under the "Leap Day" deal, North Korea pledged to suspend nuclear and missile tests and halt uranium enrichment under supervision of U.N. inspectors. In return, the U.S. promised 240,000 tons of food aid, but the April 13 launch scuppered the deal.

By launching the rocket, Davies said the North's new leadership has "sent a signal that they can't be trusted to follow through on their own undertakings and promises."

"Words are no longer, quite frankly, interesting to us. What we want to see is action from North Korea," the U.S. envoy said.

North Korea previously conducted nuclear tests in 2006 and 2009, after the U.N. imposed sanctions against its rocket launches.

Late last week, the Group of Eight world leaders warned North Korea it would face further sanctions if it conducts further "provocative acts," expressing "deep concerns" over the North. (Yonhap)