NEMURO, Hokkaido (Kyodo) Chief Cabinet Secretary Yukio Edano on Saturday flew over Russian-held Kunashiri Island and the Habomai islet group, which Japan has long claimed, and expressed willingness to seek a breakthrough in the territorial dispute between Tokyo and Moscow.

Edano, who doubles as minister in charge of the Northern Territories, as Japan refers to the four disputed islands off Hokkaido, took in an aerial view of the isles aboard a Japan Coast Guard plane. The Cabinet Office said he is the first incumbent chief Cabinet secretary to view them.

"I'm sure Japanese people will show more interest in and raise their voices on the territorial issue once they realize that the islands lie very close to them, like I just did," Edano said. "I hope negotiations (with Russia) make substantial progress."

His trip came as the spat over the islands of Etorofu and Shikotan, as well as Kunashiri and the Habomai islet group, has worsened due to a series of visits to them since last fall by top Russian officials, including President Dmitry Medvedev.