North Korea has informed China of its readiness to conduct up to two additional nuclear tests in 2013, an informed insider in Beijing told Reuters.
"It's all ready. A fourth and fifth nuclear test and a rocket launch could be conducted soon, possibly this year," according to the source.
The isolated state has threatened to carry out "stronger measures" if it is punished by the U.N. Security Council for Tuesday's nuclear test -- the North's third in less than a decade.
The United States can stave off further underground nuclear trial blasts by convening bilateral meetings with North Korea and giving up efforts to undo its government, said the source, who has access to senior officials in Beijing and Pyongyang. The North also wants a formal peace agreement for the 1950-53 Korean War.
There had been speculation that this week's event could involve the detonation of two devices at the Punggye-ri test site. "I had considered it quite possible that they may conduct two nuclear tests simultaneously," former Los Alamos National Laboratory Director Siegfried Hecker told the Los Angeles Times. "Since they did not, they may have another nuclear device ready to test and they have another test tunnel, what we call the South Portal, ready to go."
South Korea is attempting to persuade the 15-member Security Council to pass a resolution that would include language authorizing the use of armed force to ensure sanctions targeting North Korea are implemented, as allowed by Chapter 7 of the U.N. Charter, the Yonhap News Agency reported on Friday. That could involve interdiction of North Korean cargo ships believed to be transporting atomic or missile part.
Seoul hopes to see a new sanctions resolution passed before March, according to one envoy.
Outgoing South Korean President Lee Myung-bak on Friday said only an end of the Kim family regime would cause Pyongyang to turn away from its nuclear weapons ambitions, Agence France-Presse reported. "We cannot hope the North will part with its nuclear program until its regime changes or collapses."
South Korea's Nuclear Safety and Security Commission on Thursday said after examining eight samples it had yet to find signs of radioactive emissions from the North's test site, BBC News reported. Detection of unusual radionuclides near the test site would confirm that the seismic waves detected on Tuesday were the result of a nuclear explosion and not a conventional effort that was rigged to appear atomic in nature.
The yield of Tuesday's blast is subject to different estimates from nations, the Korea Herald reported on Friday.
The South Korean military estimates an explosive force of 6-9 kilotons while Germany's official geological research institute has calculated a yield of 40 kilotons. U.S. scientists have estimated a yield of "several kilotons" and specialists in Russia are projecting a yield in excess of 7 kilotons.