New satellite pictures have suggested that North Korea has resumed activity at a nuclear site following its recent atomic test, which was globally condemned, a U.S. think tank has said.
The U.S.-Korea Institute at Johns Hopkins University said that 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, the Japan Times reports.
Writing on the institute's 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.
According to the paper, 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." (ANI)