South Korea is carefully monitoring North Korea's nuclear test site to detect any signs of an imminent provocation, the Ministry of National Defense said Thursday, reiterating that Pyongyang remains "ready" to detonate another atomic device at any time.

"Our stance (that the North can conduct a nuclear test at any time) remains unchanged," ministry spokesman Moon Sang-gyun during a regular press briefing.

"(The North) has completed preparations (for a test) at the Punggye-ri test site. We are continuously monitoring the developments there," he added.

A source familiar with the activities at the nuclear test site in the country's northwest said that movements of workers and vehicles are still seen in recent satellite imagery -- a sign that preparations for an underground nuclear experiment are continuing.

Seoul officials and experts have said that the communist regime remains "technically ready" to conduct another nuclear test, and that the test would come depending on the North's leadership's reading of the political situation.

Pyongyang was expected to carry out its fifth nuclear test before a key congress of the ruling Workers' Party of Korea (WPK) that ended on Monday, to show off the country's nuclear capabilities and bolster his legitimacy amid worsening economic hardships caused by crippling economic sanctions. (Yonhap)