Main opposition leader visits Marine Corps unit

"At the time of the torpedo attack on the (South Korean) warship Cheonan, a North Korean submersible sneaked into (the South Korean waters) and ran away after striking the vessel, but the (South Korean) Navy failed to detect it."

Moon Jae-in, chairman of the main opposition New Politics Alliance for Democracy, made the remark during his visit to a Marine Corps unit in Gimpo, Gyeonggi Province on Wednesday, asking the marines to maintain a watertight security posture.

"Tomorrow (Thursday) is the fifth anniversary of the attack on the Cheonan. Have you strengthened your readiness posture against the North`s submarine infiltration?" he asked. Moon used the term "attack," apparently conscious of the controversies over the use of the expression "Cheonan`s sinking" in the advertisement materials for his presidential campaign in 2012.

Moon, an ex-Special Forces paratrooper, got on board a landing vehicle on the day wearing camouflage cream on his face. While inspecting the marines` combat equipment, he recalled his days in the military. "I carried an inflatable boat all the time," he said. "I used (diving apparatuses) many times, although they were far more primitive then."

Earlier in the day, Moon visited the campaign office of Shin Dong-geun, an NPAD candidate running in Incheon for the April 29 parliamentary by-elections, and held the party`s supreme council meeting. "We warn North Korea that we will not tolerate any military threats or provocation."