North Korea has facilities on standby to test a nuclear explosion and could do so at any time, the chief of South Korea's main spy agency said Monday, according to Yonhap news agency.

Kim Seung-kyu, head of the National Intelligence Service, said, however, that there is no sign that a test is imminent, Yonhap said.

"Facilities for a nuclear test is always on standby and considering the North's capability, the possibility (of a test) is always open," Kim told a parliamentary meeting.

CountryWatch: North Korea