SEOUL, May 25 (Xinhua) -- South Korean troops are placed on a heightened alert level as the Democratic People's Republic of Korea (DPRK) on Monday conducted a second nuclear test, along with a short-range missile launch, Seoul's defense officials said.

    The Joint Chiefs of Staff said South Korean troops stepped up the guard against the DPRK, adding that this week's three-day workshop of over 400 general-grade officers were postponed as they had to return to their posts and stay on guard at least until next week.

    Earlier in the day South Korea's defense ministry said it launched a "crisis management team" of general-level officers.

    "The team will come up with measures to respond to the nuclear test," said Lee Bung-woo, a spokesman at the Ministry of National Defense.

    The spokesman also said that the South Korean-U.S. Combined Forces Command has expanded the amount of information exchanges between the two forces.

    Meanwhile, Defense Minister Lee Sang-hee is considering adjusting its pre-arranged schedule to visit China and Singapore, he added.

    The military decision came as South Korea's presidential office reported it has detected an "artificial earthquake" in the DPRK, which was later confirmed by the DPRK as its 2nd nuclear test.

    The test site is located 10 to 15 km away from the first site in Kilju in North Hamkyong Province.

    The DPRK has recently threatened to conduct another nuclear test after the U.N. Security Council announced a presidential statement condemning the April 5 rocket launch.

Backgrounder: DPRK's two nuclear tests