Russian President Vladimir Putin made a visit Thursday to the Japan-claimed island of Etorofu, according to a report by Russian news agency Tass.

Etorofu is among a group of islands off the east coast of Hokkaido that have been occupied by the former Soviet Union since the end of World War II and are claimed as Japanese territory by Tokyo.?

The visit is the first by a Russian president to the disputed islands since President Dmitry Medvedev made the first such trip, to Kunashiri, in November 2010. Medvedev and Mikhail Mishustin visited the islands several times as Russian prime minister since then. It was Putin¡¯s first visit to any of the islands, which are known as the Northern Territories in Japan.

Putin, who has been visiting Russia¡¯s Sakhalin region this week to attend drills by the Russian Navy¡¯s Pacific Fleet, visited a fish processing factory on Etorofu, the news agency said.

Foreign Minister Toshimitsu Motegi issued a statement protesting Putin¡¯s visit.

¡°We strongly protest the visit. The Northern Territories, including Etorofu island, are Japan¡¯s inherent territories, both historically and under international law,¡± Motegi said.

The visit comes during the o-Bon holiday, during which many people in Japan return to their hometowns and honor their ancestors.

This is a developing story. Updates to follow.