South Korea’s military said Thursday it is carefully monitoring North Korean nuclear and missile facilities. The statement came after the country’s spy agency told lawmakers that new activity was detected at a research center where the North is believed to build long-range missiles targeting the US mainland. Defense Ministry spokeswoman Choi Hyun-soo said the US and South Korean militaries are closely coordinating intelligence over the developments at the North’s missile research center in Sanumdong on the outskirts of the capital, Pyongyang, and also at a separate long-range rocket site. A lawmaker who attended a closed-door intelligence briefing told AP that the National Intelligence Service director said his agency had monitored increased vehicle movement at the Sanumdong facility.