The Coast Guard said Monday it has deployed additional aircraft on the south coast to patrol nearby waters, including the rock outcropping of Ieodo, to which China recently laid claim.

The CN-235 fixed-wing airplane can fly for up to seven hours at a speed of 400 kilometers per hour and is fitted with a top-class scan radar, thermal equipment, flares and equipment for dropping lifeboats, the maritime police said.

The move comes as South Korea has lodged protests against China for laying claim to Ieodo, which lies within the overlapping exclusive economic zones of the two countries.

Although an international maritime law stipulates that a submerged rock cannot be claimed as territory by any country, South Korea effectively controls Ieodo, which is closer to it than any other country.

South Korea has taken steps to reinforce its jurisdictional control over the islet and in 2003 built an unmanned maritime research station on it to monitor weather conditions and survey maritime features in the area.

Ieodo is located 149 kilometers southwest of Korea's southernmost island of Marado and 247 km northeast of the nearest Chinese island Tongdao. (Yonhap News)