South Korea’s Defense Ministry came under fire Wednesday for a belated response to Tokyo’s repeated claims of sovereignty over the easternmost islets of Dokdo in a Korean-language summary of its annual defense whitepaper.

In the morning, the ministry called in a defense attache from the Japanese Embassy in Seoul to protest Japan’s description of the islets as part of its territory on a map, after the embassy delivered 57 copies of the whitepaper last Friday. It was the first time that the summary in Korean contained Tokyo’s claim to Dokdo.

“We issued a strong protest to the Japanese defense attache in the morning so that this kind of inappropriate act would not be repeated,” a ministry official told reporters, declining to be named. “We have returned all 57 copies to the embassy.”

The Japanese Embassy delivered the copies to the ministry’s information division last Friday. The copies were handed over to the ministry’s division in charge of East Asian affairs on Tuesday.

A ministry official said that the response to Japan’s claim to Dokdo, called Takeshima in Japan, came late because the official who first received the copies was not aware of their importance as they did not concern any urgent security issues.

Japan has claimed sovereignty over Dokdo in its defense whitepaper for the past decade.

The tensions over Dokdo flared up at a time when the two countries are attempting to improve their ties. This year marks the 50th anniversary of the normalization of their diplomatic relations, and growing security threats from the North have underscored the importance of security cooperation between the two neighbors.

The diplomatic spat over Dokdo is expected to escalate further next month when the Japanese prefecture of Shimane observes its Takeshima Day. Since 2013, the Abe government has sent senior officials such as vice minister-level figures to attend a ceremony to mark the day, prompting strong protests from Seoul.

Drawing the ire of Koreans, Tokyo has also created a video clip to reassert its claim to Dokdo. A state agency in charge of territorial issues reportedly posted the 17-minute clip on YouTube on Dec. 24 to argue that Japanese people fished in waters surrounding Dokdo in the past.

Japan incorporated Dokdo as part of its territory in 1905 before colonizing the entire peninsula. Korea has been in effective control of them with a small coast guard unit posted there since its liberation in 1945.

Along with the territorial issue, historical antagonism has been a major hurdle to improving the bilateral ties.

Seoul has raised pressure on Tokyo to compensate and fully atone for its wartime sexual enslavement of Asian women, which it regards as a broader human rights issue beyond the bilateral relationship. However, Tokyo has yet to respond to Seoul’s demand, saying that this issue has already been settled under a 1965 bilateral normalization pact.

By Song Sang-ho (sshluck@heraldcorp.com)