Though North Korea has threatened to take stronger measures to protect its sovereignty following its Feb. 12 nuclear blast, experts say the isolated country may need several weeks to prepare for additional atomic tests.

The diplomatic source in Beijing, who did not wished to be identified, claimed Pyongyang is very conscious of China and about concerns of radioactive contaminants from its underground test.

“After the latest test, the North seems to be carefully checking the condition of the tunnel used under Mt. Mantap at the Punggye-ri test complex,” he said, adding that this check means it will be weeks before the country is ready to detonate another atomic device. (Yonhap News)