The Navy on Friday dismissed Japan's claim that a South Korean warship directed fire-control radar at Tokyo's patrol aircraft a day earlier, saying the neighboring country misunderstood its operation to help a North Korean ship drifting near a sea border.

Japan's Kyodo News reported that Japanese Defense Minister Takeshi Iwaya said the South Korean vessel targeted the Maritime Self-Defense Force's P-1 patrol aircraft and that Tokyo lodged a protest with Seoul.

"The vessel used fire-control radar not because of the P-1, which was flying in Japan's air defense identification zone, but because we tried to trace a North Korean warship drifting near the inter-Korean sea border," a Navy official told Yonhap News Agency on condition of anonymity.

The official added that the Navy ship appears to have used both fire-control radar and navigation radar to more accurately locate the North Korean vessel moving toward the Northern Limit Line in the East Sea.

"We have already explained this to the Japanese government, stressing that we did not target the Japanese aircraft. It is a misunderstanding," he said.

Seoul's Ministry of National Defense also rejected Tokyo's claim.

"Our military was carrying out a normal operation. It used radar during the operation but not for the purpose of tracking Japanese patrol aircraft," it said in a text message sent to reporters.

"We have explained the aforementioned to the Japanese side but will explain it sufficiently enough to ensure that there will not be a misunderstanding." (Yonhap)