Story highlights South Korea says a test can happen as soon as North Korean leader Kim Jong Un orders itUS maintains presence of WC-135 Combat Shadow aircraft in region to conduct air sampling after possible testWashington (CNN) Specific intelligence indicators now show that North Korea is ready for its sixth underground nuclear test at any time, two US officials told CNN on Friday. Recent satellite imagery indicates a potentially significant change at the Punggye-ri test site, the officials said. JUST WATCHED One thing to know about North Korea's missiles Replay More Videos ... MUST WATCH One thing to know about North Korea's missiles 01:03The South Korean government issued a statement Friday saying a test can happen as soon as North Korean leader Kim Jong Un orders it. "It is assessed that North Korea is ready to carry out a nuclear test anytime if its leadership decides to do so," Lee Duk-haeng, spokesman for South Korea's the Ministry of Unification, said in a press briefing. He said that "South Korean and US intelligence authorities evaluate that North Korea is ready to carry out a nuclear test anytime on the leadership's decision."

Source: CNN March 24, 2017 18:11 UTC