Also among the tourists were those from Britain, Australia, Switzerland, the Netherlands and New Zealand, according to Russian news site Sakhalin.info.

It seems that the foreign tourists obtained visas from Russia in making the visit to the island in question, called Etorofu in Japan.

Some Russians traveled with the foreign tourists, the report said.

The tourists visited a hot spring area and other places during their six-hour stay on the island, according to the report. They also visited the Kamchatka Peninsula in the Russian Far East region.

Japan's government is asking Japanese nationals not to enter the four islands, known collectively as the Northern Territories in the country, saying that a visit could amount to recognizing Russia's jurisdiction over the islands.

The islands, located off Japan's northernmost prefecture of Hokkaido, were seized by the former Soviet Union from Japan at the end of World War II and are claimed by Japan. The dispute has prevented Tokyo and Moscow from concluding a peace treaty to formally end their wartime hostilities. (Jiji Press)