President Moon Jae-in visited a front-line military unit on a western border island on Thursday and hailed Marines there for their hard work, Cheong Wa Dae said.

Moon flew by helicopter to Baengnyeong Island near the western sea border with North Korea and began his visit by paying his respects at a memorial dedicated to the 46 sailors killed in the North's sinking of the Cheonan corvette in 2010, his spokeswoman Park Kyung-mee said in a written briefing.

Moon then visited the headquarters of a Marine brigade to be briefed on the unit's work and mounted a forward observation post to encourage the troops there.

He extended his special thanks to the troops for serving in one of the most important military areas where they must constantly remain on high alert without being able to leave the island easily.

During a meal with the brigade's commanders, the president stressed the importance of looking after the troops' human rights and welfare.

"I ask that you make sure these servicemembers, who are working in difficult conditions, return to their families healthy and more mature," Moon said, according to Park.

The president was accompanied on the trip by first lady Kim Jung-sook(Yonhap)