"It's the first time that the approval rating fell below 70 percent in a weekly survey," the polling agency said. "The ratings of President Moon and his Democratic Party fell together as the sense of a security crisis in the wake of North Korea's sixth nuclear test continued."

Moon's rating rebounded a bit following his decision to deploy additional launchers for the US THAAD missile defense system, the agency said, adding that the score rose even among liberals who have expressed opposition to the deployment.

Moon's Democratic Party also saw its rating drop 1.6 percentage point to 49.7 percent, the second time the party's popularity has fallen below 50 percent since May's presidential election.

The main opposition Liberty Korea Party had an approval rating of 16.7 percent, up 0.3 percentage point from a week earlier, while the minor opposition Bareun Party and the People's Party had approval ratings of 6.3 percent and 5.7 percent, respectively. (Yonhap)