SEOUL, South Korea — South Korea’s National Intelligence Service said it believed that North Korea was preparing for another nuclear test, but not in the near future, according to lawmakers who attended a closed-door parliamentary session with officials from the spy agency on Tuesday.

The legislators Lee Cheol-woo and Shin Kyoung-min, who briefed members of the South Korean news media on the session, provided no other details except that South Korea was monitoring the North’s nuclear facilities through “human” and “technological” means.

The spokesman’s office at the intelligence service refused to comment on the lawmakers’ briefing.

North Korea conducted three nuclear tests between 2006 and February 2013, provoking sanctions from the United Nations Security Council. Analysts in the region have previously said that the North might conduct a fourth test to master the technology to build a nuclear warhead small enough to mount on an intercontinental ballistic missile, although the North claims it already has such know-how.