Chief Cabinet Secretary Yukio Edano on Saturday inspected disputed northern islands off Hokkaido from the air, local media reported.

Edano, who is also Japan's minister in charge of Northern Territories issues, has thus become first top government spokesman to view the islands, known as the Northern Territories in Japan and the Southern Kurils in Russia.

Japan's Chief Cabinet Secretary Yukio Edano views the group of islands, called Northern Territories by Japan and Southern Kuriles by Russia, from an aircraft off Japan's northern island of Hokkaido February 19, 2011.

Voicing his hope to make a breakthrough in negotiations with Russia, Edano said, "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."'

The top government spokesman's move came as the dispute between Japan and Russia escalated due to a series of visits to the islands by top Russian officials, including President Dmitry Medvedev.

On Tuesday, Japanese Foreign Minister Seiji Maehara snubbed cautionary comments over the islands made by Sergei Naryshkin, chief of staff of the Russian Presidential Executive Office, who said that Tokyo's recent public statements over the islands and its continued unfounded territorial claims "could not but meet with an adequate reaction of the Russian side."

Maehara reiterated his view that the four islands are unequivocally an "integral part of Japan in terms of history and international law."

The islands of Etorofu, Kunashiri, Shikotan and the Habomai rocks were held by Japan until the end of World War II when Japan surrendered. The Yalta Conference ceded the islands to the Soviet Union, and Soviet forces occupied the island chain in September 1945. Japan challenged the Soviet right to the islands and demanded their return to Japan.

The dispute over sovereignty is also largely concerned with the somewhat ambiguous San Francisco Peace Treaty between the Allied Powers and Japan inked in 1951.

The territorial dispute has prevented the two countries from signing a postwar peace treaty.