Seoul, South Korea (CNN) -- The top U.S. envoy for North Korea warned Pyongyang Monday against a possible third nuclear test.
"I think it would be a serious miscalculation and mistake if North Korea works to engage in a nuclear test," Glyn Davies told reporters following a meeting with his South Korean and Japanese counterparts in Seoul.
Many analysts assume an atomic test by North Korea is just a matter of time following the failure of Pyongyang's rocket launch on April 13. Two previous rocket launches in 2006 and 2009 were followed by a nuclear test.
Davies pointed to the international condemnation following the recent rocket launch, saying Pyongyang knows what kind of response a further provocation would elicit. Pyongyang had agreed a deal with the Washington just weeks before the April launch which guaranteed no rocket or missile tests and access for nuclear weapons inspectors in return for food aid.
"They've sent a signal that they can't be trusted to follow through on their own undertaking on their own promises," Davies said.
But Davies did leave the door open for further negotiations, saying the U.S. has a dual track policy of engagement on the one hand, pressure on the other. He insisted that the "engagement aspect remains open."
G8 leaders meeting in the United States over the weekend agreed that North Korea faces further isolation if it continues its pursuit of a nuclear program.
CNN's K.J. Kwon contributed to this report.