The belief that foreign troops are necessary for South Korea’s national defense against North Korea reflects a “submissive mindset,” President Lee Jae-myung said Sunday, vowing to use new technologies to strengthen the military in the face of manpower shortages.

In a social media post, Lee pledged defense reforms to build “a nation that will never again be invaded or dependent on others for its defense,” rejecting what he characterized as alarmism about a projected decline in troop numbers.

The post linked to a reportabout defense ministry data showing that South Korea’s active-duty forces would fall from 450,000 in