The four Russian-held islands off Hokkaido are Japanese territory regardless of Russia's actions, Foreign Minister Seiji Maehara reiterated Wednesday, brushing off recent concerns Moscow is strengthening its control over the area.

"No matter who goes to the islands, regardless (of rank) or whether (Russia) strengthens its military, it doesn't change Japan's legal position that they are the inherent territory of our country," Maehara told the Lower House Budget Committee.

Russia's Interfax news agency reported Tuesday that Foreign Minister Sergey Lavrov urged Japan to accept the results of World War II, at the end of which the Soviet Union seized the four islands, saying negotiating with Japan would otherwise be meaningless.

Russia has also been reaching out to Chinese and South Korean companies to jointly develop the islands. On Wednesday, Foreign Ministry Press secretary Satoru Sato said the ministry has yet to confirm the facts about such plans, but in general such activities would not be tolerable.

"In general, obtaining a Russian visa and (going to the islands), the inherent territory of our country, or doing business there is unacceptable" because it would effectively recognize Russia's control, Sato said, adding the government has and will continue to express its position to Beijing and Seoul.