The United States has backed Japan's sovereignty over four islands controlled by Russia after Vladimir Putin became the first Russian president in 15 years to visit the disputed territory, prompting Tokyo to summon Moscow's ambassador and describe the trip as "absolutely unacceptable."
"The United States remains unwavering in its support of its most important ally and in its recognition of Japanese sovereignty over the Northern Territories," the US ambassador to Tokyo George Glass said on X.
"At a time when the US-Japan alliance is dedicated to cultivating prosperity across the Indo-Pacific, we strongly oppose any action that undermines its peace and stability," Glass added.
Russian-Japanese relations have long been dogged by the four southernmost islands in a volcanic chain off the coast of Hokkaido seized by the Soviet Union following an invasion in August 1945, in the final days of World War II.
Moscow broke its formal neutrality with Japan just days before the invasion.
