SEOUL, Dec. 28 (Xinhua) -- South Korea's military on Thursday kicked off a two-day maritime defense drill near the Dokdo islets, called Takeshima in Japan, local media reported.

South Korea's Navy was quoted by local media as saying that the Dokdo defense exercise will be conducted for two days from Thursday to carry out the regular drill aimed at defending against an invasion of external forces.

Mobilized to the drill would be five battleships, including a 3,200-ton destroyer, as well as maritime patrol aircraft, fighter jets and helicopters.

It marked the second defense drill to protect the Dokdo islets since the Moon Jae-in government was inaugurated in May. The latest was staged in June.

Japan has strongly protested against the exercise as it laid territorial claims to the rocky outcroppings lying roughly halfway between South Korea and Japan.

South Korea regained the islets after liberating from the Japanese colonial rule of the Korean Peninsula from 1910 to 1945. The islets were incorporated into Japan during the colonization.