Biden recommits to Japan's defense amid China tensions

US President Joe Biden voiced resolute support for Japan's national defense amid long-standing territorial disputes with China, the White House said Wednesday.

Biden spoke earlier in the day with Japanese Prime Minister Yoshihide Suga in a telephone call that focused on "the policy issues and global challenges that Japan and the United States will face together," the White House said in a statement.

"They discussed the U.S.-Japan alliance and affirmed its importance as the cornerstone of peace and prosperity in a free and open Indo-Pacific," it said. "The leaders also discussed the United States’ unwavering commitment to the defense of Japan under Article 5 of our security treaty, which includes the Senkaku Islands."

The uninhabited islands are formally administered by Japan but are also claimed by China and Taiwan. Japan and China have in recent years increasingly sent warships to surrounding waters, raising fears of a possible clash between the east Asian powers over the territory, which may boast significant natural resource deposits.

Under Article 5 of the Japan-US Security Treaty the US is obliged to intervene if there is a military attack on Japanese territory, which the White House made clear includes the islands.

US officials have been warning of China's more assertive role on the global stage, particularly in the South China Sea where it shares a host of territorial disputes with regional countries, including Japan.

During his call with Suga, Biden "reaffirmed to the Prime Minister his commitment to provide extended deterrence to Japan," the White House said in a likely reference to military arms.