South Korean officials are increasingly convinced that North Korea is getting ready for another nuclear test amid brisk activity at its test site in Punggye-ri, North Hamgyong Province.
In a press briefing here on Tuesday, Defense Ministry spokesman Kim Min-seok said, "We're detecting signs of various movements at the nuclear test site. It seems that the North can conduct a nuclear test at any time."
Kim quoted reports that North Korean officials are talking internally about an imminent "big thing" before April 30, though it is unclear whether this could be a nuclear test or a provocation near the front line.
Where these reports came from is unclear since they were not found in the North Korean state media. It would be unprecedented for officials here to disclose information gained through intercepts or intelligence sources.
The ministry and Joint Chiefs of Staff put a taskforce on round-the-clock duty on Monday in case the North plans a provocation to coincide with U.S. President Barack Obama's visit to Seoul on Friday and Saturday.
The taskforce led by a two-star general consists of senior staff at the ministry and the JCS.
"In the past, the North used delaying tactics or deception after it made preparations for a nuclear test, so we're keeping that in mind," a military source said.