Tokyo has taken the hardest line in the six-nation talks, refusing to fund the deal due to a dispute over Pyongyang's past kidnappings of Japanese civilians.
"North Korea has only one card in hand and that is its nuclear programme
Rahy, Tehran, Iran
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Meanwhile, North Korea's nuclear envoy arrived in Beijing on Tuesday for a fresh round of disarmament talks a day after the International Atomic Energy Agency (IAEA) confirmed that Pyongyang had shut down its main reactor in Yongbyon.
Envoys from the two Koreas, Japan, China, Russia and the US will negotiate for North Korea to surrender its atomic secrets in the second phase of nuclear disarmament agreed under the February pact.
Kim Kye-gwan flew into Beijing on Tuesday for two days of scheduled talks that will kick-off on Wednesday.
He told broadcaster APTN in Pyongyang "there should be discussion on how to define the targets of the second phase, the obligations for each party, and also the sequence of the actions".
The shutdown of the Yongbyon plant has paved the way for a first-ever ministerial-level meeting to negotiate an end to the North's nuclear weapons programme.
Sean McCormack, a US state department spokesman, said the closure of the Yongbyon complex, the source of Pyongyang's weapons-grade plutonium, was the "trigger mechanism" for ministerial-level talks.
"It makes a ministerial-level meeting possible. We'll see exactly when in the coming weeks that's going to be. I don't have a date for you right now," he said.