North Korea appears ready to conduct its fourth nuclear test, but no imminent signs have been detected at its main site on its northeastern tip, South Korean Defense Minister Kim Kwan-jin Monday. According to Yonhap news Agency, Kim said Pyongyang has prepared for an underground nuclear test at the Punggye-ri site, which was used for the third atomic test a year ago, and has taken "initial steps" for a missile launch at its northwest test site in Tongchang-ri. "These things (the nuclear test and the missile launch) depend on the decision by the North Korean leadership. As seen in the past, the long-range missile test and the nuclear test are connected to each other," Kim was quoted as telling lawmakers during a parliamentary interpellation session. "We are closely watching (the North Korean military) to prepare against any provocations." The North is known to have tested an engine for its KN-08 long-range missile just before last year's atomic test, which is seen as efforts to master the technology to build a nuclear-tipped intercontinental ballistic missile. According to the National Intelligence Service in October, Pyongyang is believed to have conducted several missile engine tests at the Tongchang-ri site last year and has been renovating the test facility since May 2013. Last month, 38 North, a website specializing in North Korea-related news run by the US Korea Institute of Johns Hopkins University, said a possible test of a rocket engine used by the KN-08 took place between late December 2013 and early January, citing satellite images.