South Korea has rejected a protest by Japan over Seoul's annual defense report that reaffirms its bid to protect the easternmost islets of Dokdo, a senior official said Monday.

Japan recently sent the South Korean government an official letter protesting the defense white paper that made clear Seoul's sovereignty over Dokdo, which Tokyo has also claimed as its own.

In a rebuttal letter to Japan, South Korea reiterated that, "Dokdo is an integral part of Korean territory historically, geographically, and under international law," the foreign ministry official said on the condition of anonymity.

Also, the letter said Japan's latest protest was "not worth consideration," the official said.

The defense white paper was published on Dec. 21, days before Japan's parliament elected Shinzo Abe as its new prime minister.

Abe, Japan's seventh prime minister in six years, plans to send envoys to South Korean President-elect Park Geun-hye next month, in a gesture of reconciliation amid strained bilateral ties.

Dokdo, which lies closer to South Korea in the body of water between the Korean Peninsula and Japan, has long been a thorn in relations between the two countries. South Korea keeps a small police detachment on the islets, effectively controlling them.

Relations between South Korea and Japan have been frayed since President Lee Myung-bak made a visit to Dokdo in August, the first by a South Korean president, and Japan strongly protested the move and renewed its claim to the East Sea islets. (Yonhap News)