New activity detected at North Korea nuclear site


North Korea has resumed activity at a nuclear site following its globally condemned atomic test last week, a U.S. think tank said, amid fears that Pyongyang will carry out more explosions.

Examining satellite photos, the U.S.-Korea Institute at Johns Hopkins University said Wednesday it detected a rise in traffic at the Punggye-ri site but cautioned that there is not enough evidence to assert that a new test is in the works.

The think tank reported that there had been no sign of vehicles or people moving at the site for a day after North Korea carried out its third nuclear test Feb. 12, but that activity had resumed by Feb. 15.

Writing on the institute’s 38 North blog, analysts Jack Liu and Nick Hansen said the change over just a few days may indicate Pyongyang “took safety precautions to ensure radioactivity levels were sufficiently low before sending personnel back into the area.”

North Korea is believed to have tightly sealed the site, making it difficult for the United States and other nations to detect from the air whether uranium had been used in the device — which would prove Pyongyang has a second nuclear method in addition to its plutonium program.

The analysts also found activity in two different parts of the site. They said that if the North detonated the bomb in a tunnel in the northern area, “then the southern tunnel would be readily available for a fourth test.”

North Korea likely used the northern tunnel area in 2009 for its second nuclear test, but it is not known in which area the latest underground detonation was carried out. The analysts said another reason why activity appeared to increase this month was the melting of snow that fell the day after the nuclear test.

Despite widespread international condemnation, Pyongyang has taken on a defiant tone since its latest explosion of an atomic device, leading to fears that it will conduct another blast or long-range ballistic missile test.