Japanese diplomats were summoned by South Korean authorities on Tuesday after Tokyo renewed its claim in a defense white paper to a disputed group of islands that lie between the two countries.

The claim comes a day after Seoul blocked three Japanese lawmakers from entering South Korea on a visit that was meant to reinforce Japan's claims to the islands.

Nobukatsu Kanehara, a senior minister at the Japanese embassy in Seoul, was ordered to appear at the foreign ministry to explain his country's latest claim, while a Japanese defense attache was summoned to the defense ministry.

In Tokyo on Tuesday, Chief Cabinet Secretary Yukio Edano protested South Korea's treatment of the three legislators and said Japan will approach the issue firmly and with a broad perspective.

South Korea's defense ministry warned that the Japanese claim is an obstacle to improved military cooperation between the two countries.

Tokyo's claim to the islands, known in Japan as Takeshima and in Korea as Dokdo, has been restated in the annual defense report for several years. But South Korea is responding more forcefully this year in light of rising diplomatic tensions over the islands.

The dispute intensified in June when South Korea's flag carrier Korean Air passed over the islets during a demonstration flight of its new Airbus A380 super-jumbo airliner. Japanese officials called the flight an infringement of Japanese air space and banned foreign ministry officials from using the Korean airline for a month.

The Japanese lawmakers then announced their intention to “inspect” an island near the disputed chain. The three were refused entry when they arrived Monday at the international airport in Seoul. South Korean protesters tore Japanese flags and set fire to pictures of the legislators outside the airport.

Edano criticized the entry ban on the lawmakers as unacceptable and asked South Korea to reconsider it.

The islets have been under effective South Korean control since the end of Japanese colonial rule after World War II.