South Korean government has expressed strong regret over Japan's reiteration of territorial claims over Dokdo islets in its annual defense white paper. Seoul vowed to firmly respond to Japan's latest sovereignty claim over Dokdo in the East Sea, saying that such a move will not help relations between the two countries. The Foreign Ministry called in Japan''s Minister and Deputy Chief of Mission to South Korea Nobukatsu Kanehara on Tuesday morning. The ministry also conveyed a diplomatic cable to the second-highest Japanese diplomat in Seoul, KBS World Radio reported. This is a stronger action than the response Seoul made last year against Japan''s territorial claim in its 2010 defense white paper. At that time, the South Korean government summoned Hirotaka Matsuo, political councilor at the Japanese Embassy in Seoul. The government is also considering strengthening its effective control of the Dokdo islets and revealing of the construction of facilities there. A government official said that Dokdo clearly belongs to South Korea in terms of history, geography and international law, adding that Japan''s claim does help relations between the neighboring countries.