Korea's military stepped up security in the East Sea on Friday as President Lee Myung-bak made a landmark visit to the easternmost islets of Dokdo, military officials said.

"The military increased the number of Air Force combat planes and Navy vessels patrolling (near Dokdo)," a senior official said, asking for anonymity as he is not authorized to speak about military information to the media.

Lee visited the rocky outcroppings lying in the East Sea around halfway between the Korean Peninsula and Japan from nearby Ulleung Island. The trip made Lee the first South Korean president to visit the islets.

The Air Force's main fighters, F-15Ks and KF-16s, and Navy ships patrolled around Dokdo as Lee neared the islets, according to military officials. An early warning and control plane called the "Peace Eye" also conducted a reconnaissance mission, they said.

Lee's historic visit to the islets comes after Japan last week renewed claims to them in its annual defense "White Paper" and just days before Korea observes Liberation Day on Wednesday, to celebrate Korea's independence from Japan's 1910-45 colonial rule.

Korea will also go ahead with planned joint military exercises in waters near Dokdo next week, officials said, noting the exact date has not been confirmed.

The biannual exercise will be carried out under a scenario in which the Army, Navy, Air Force and Coast Guard conduct a joint operation to drive out a vessel that has invaded Korea's territorial waters near Dokdo.

Korea has kept a small police detachment on Dokdo since 1954. .(Yonhap)