North Korea appears to be making preparations for its next launch of a spy satellite, although there are no signs of an imminent launch, South Korea's military said Thursday. Last November, Pyongyang successfully placed its first military spy satellite into orbit after two failed attempts earlier that year. It has since vowed to launch three more spy satellites this year. "While there are activities preparing for an additional military satellite launch by North Korea, there are no signs as of now of an imminent (launch)," Col. Lee Sung-jun, spokesperson of the Joint Chiefs of Staff, told reporters in a briefing. Lee said South Korean and U.S. intelligence authorities are in close coordination to track North Korea's military activities, but did not provide further details. Earlier this week, 38 North, a U.S.-based website monitoring North Korea, said an "expanse of blue material" -- possibly a covering -- was spotted on the launch pad of the North's satellite launching station, citing commercial satellite imagery. 38 North said the purpose of the material was unclear but noted the pad likely remains ready to use, raising speculation that a launch may be imminent. Last week, South Korea's Defense Minister Shin Won-sik said there was a high possibility the North could stage the satellite launch at the end of this month. Source: Yonhap News Agency