Japanese fighter jets were scrambled on Thursday in response to what Japan said was an intrusion into Japan's airspace by Russian fighters according to Tokyo.

The intrusion, into northern Japanese airspace, which lasted all of a minute,near Hoakkaido by Russian jets came after the Prime Minister of Japan pledged to resolve the 60-year-old dispute between the two countries for four islands off of the northern coast of Japan. Russian denied that the intrusion took place after Tokyo lodged a protest over the incident with Moscow.

The lingering dispute had its beginnings during the last days of World War II when Russia began its operations in the territories around Japan.

On August 8th of 1945, two days after the United States dropped the atomic bomb on Hiroshima, Russia declared war on Japan. By the next day Russia invaded the Japanese puppet state of Manchukuo as the United States was dropping the second bomb on Nagasaki. On August 15th, Japan’s emperor, Hirohito surrendered to the allies in a recorded message. Russia was one of those allies.

By August 18th of that year and into September, Russia mounted a campaign to take the Kuril Islands. By September, Russia occupied all of the islands in the chain.

Japan has contended that Russia continued its actions against Japan long after Japan had issued a surrender.

By 1951 and the treaty of San Fransisco, the general agreement was that Japan was to cede the Kuril Islands and relinquish claim to them. It was at this time that Japan stated that four of the islands north of Japan were not part of the Kuril chain of islands, those islands were: the Etorufu, Kunashiri, Shikotan, and Habomai Islands. Their claim was solidified by the Treaty signed between Russia and their country in 1855 giving ownership of those islands to Japan.

By 1956, during the peace talks between Russia and Japan, Russia offered to cede control of Shikotan and Habomai if Japan would remove its claims to Etorufu and Kunashiri. Japan was about to accept this deal with Russia until the United States blocked the deal saying if it went through, the United States would keep Okinawa. The deal was never made.

In 2005, the European parliament recommended to Russia that they give back the islands in dispute. Russia protested. By 2006, Russia offered the same deal that they offered Japan in 1956.

Russian President Medvedev visited the islands in September of 2010, calling the islands “an important region of Russia.” That series of visits prompted Japan to withdraw their ambassador from Russia. By 2011, Russia began moving military assets to the islands.

Japan says that the unresolved issue of the islands in dispute has prevented a formal peace treaty with Russia.