Combined photo shows U.S. President Joe Biden (L, Getty/Kyodo) and Japanese Prime Minister Fumio Kishida. (Kyodo) 

Japan's new Prime Minister Fumio Kishida said Tuesday he received "strong words of commitment" from U.S. President Joe Biden on Washington's promise to defend the Senkaku Islands in the East China Sea.

China claims the Japan-administered uninhabited islets and calls them Diaoyu, one of several areas of concern among the United States and its allies over Beijing's growing assertiveness in regional waters.

In separate calls with Biden and Australian Prime Minister Scott Morrison, Kishida affirmed cooperation on efforts to realize a "free and open Indo-Pacific" region, the Japanese Foreign Ministry said. Kishida's call with Biden was his first with a foreign leader since taking office on Monday.

Biden strongly committed "to the defense of Japan, including the application of Article 5 of the Japan-U.S. security treaty to the Senkakus," Kishida told reporters after their roughly 20-minute conversation.

Article 5 states Washington will defend territories under Tokyo's administration from armed attack. Beijing often sends coast guard ships near the Senkakus despite Tokyo's protests.

Kishida, who was elected prime minister in an extraordinary parliamentary session on Monday to replace the unpopular Yoshihide Suga, also agreed with Biden to cooperate on global issues including COVID-19, climate change, and working toward a world without nuclear arms.

A former foreign minister, Kishida said in a press conference on Monday that China is a valuable trade partner but Japan will "say what needs to be said" regarding what he called Beijing's shortcomings in upholding freedom, democracy and the rule of law.

Biden affirmed Washington will support Tokyo in its efforts to secure the return of Japanese nationals abducted by North Korea in the 1970s and 1980s, Kishida said, adding the two leaders agreed to meet in person as soon as possible.

Composite photo shows (top row) U.S. President Joe Biden (L, Getty/Kyodo) and Japanese Prime Minister Fumio Kishida, (bottom row) Indian Prime Minister Narendra Modi and Australian Prime Minister Scott Morrison. (Kyodo)

The White House said Biden "noted that he looks forward to strengthening the relationship in the years ahead given the critical role our countries play in advancing our common vision of a free and open Indo-Pacific region, including through the Quad."

The Quad is a group of countries also including Australia and India that are stepping up cooperation to counter China's growing assertiveness.

Kishida and Morrison both voiced strong opposition to "unilateral attempts to change the status quo" in the East and South China seas and economic intimidation," the Japanese Foreign Ministry said without explicitly mentioning Beijing.

The ministry also said Kishida welcomed the recent signing of a defense deal between Australia, the United States and Britain, known as AUKUS, during the roughly 20-minute call.

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