Japan's ambassador to Russia, recalled amid the recent diplomatic spat over the disputed Kuril Islands, will return to Moscow by Sunday noon, the Kyodo news agency said. On Monday, Russian President Dmitry Medvedev became the first Russian president to visit one of the four disputed Kuril Islands, called the Northern Territories by Japan. The move triggered an angry response from Tokyo, which called the visit "regrettable" and temporarily recalled its ambassador to Russia for consultations. The Japanese government has later taken a decision to refrain from further actions of protest. Both Moscow and Tokyo have laid claim to the Kuril Islands since they were occupied by the Soviet Union at the end of World War II. The dispute over the islands has prevented Russia and Japan from signing a peace treaty to formally end World War II hostilities.