Spokesman Kim Hee-jung said Lee instructed relevant ministries to "gradually push for the military fortification" of the five islands considered vulnerable to provocations by North Korea, and called for improved living conditions for the islands' residents, South Korean news agency Yonhap reported.
"Various ministries should also cooperate in creating jobs and other conditions for residents to continue to stay there," the president was quoted as saying during a weekly Cabinet meeting.
Concern is growing that the islands near the Yellow Sea border could become ghost islands as a growing number of residents have asked the government to help them relocate to areas not under direct threat of attacks by North Korea, Yonhap said.
North Korea initiated an artillery barrage Nov. 23 on Yeonpyeong, which has about 1,400 residents and a military installation, killing two South Korean marines and two civilians.
The South Korean government Monday said it would spend $26 million to help displaced residents resettle and finance reconstruction of destroyed facilities.