The United States and Japan called for "peace and stability across the Taiwan Strait" in a joint statement on Friday following a meeting between US President Joe Biden and Japanese Prime Minister Yoshihide Suga.

It was the first time since 1969 that the US and Japan's top leaders have explicitly mentioned Taiwan in their joint statements, although their defence and foreign ministers expressed similar sentiments in a statement last month.

China regards Taiwan as a breakaway province to be reunified, by force if necessary, and has increasingly sent warplanes into the Taiwanese air defence zone.

Tokyo sees Beijing's actions as unilateral attempts to change the status quo in the East and South China seas and threats to its own security.

Mr Suga's trip to Washington, the first by a world leader since Mr Biden assumed the US presidency in January, underscored the importance of the Indo-Pacific region to the Biden administration's foreign policy and the centrality of Japan to US strategy.

Both leaders vowed to jointly take on challenges from China, whose increasingly assertive stance in the region has unsettled both nations.

At a joint press conference at the White House Rose Garden, Mr Biden announced that Japan and the US had launched the Competitiveness and Resilience Partnership, under which they would advance innovation, end the Covid-19 pandemic and guard against future ones, as well as combat the climate crisis.

The US and Japan will invest US$2.5 billion (S$3.34 billion) and US$2 billion, respectively, into developing and deploying 5G and next-generation mobile networks.

Mr Biden said the US and Japan would also cooperate on supply chains for critical sectors like semiconductors, and in research in areas such as artificial intelligence and quantum computing. China seeks to become dominant in those areas.

Mr Biden, in an implicit rebuke of Beijing, said: "Those technologies are governed by democratic norms that we both share - norms set by democracies, not by autocracies."

While China loomed large in their discussions, Japan - which counts China as its largest trading partner and the US as its military ally - was also careful to appear not to be isolating China.

Mr Suga said he and Mr Biden "had serious talks on China's influence over the peace and prosperity of the Indo-Pacific and the world at large", adding: "At the same time, we agreed on the necessity for each of us to engage in frank dialogue with China."

The leaders' statement also said they "share serious concerns" about the human rights situation in Hong Kong and Xinjiang.

Both nations are committed to taking aggressive action on climate change, said Mr Biden, who will host world leaders at a virtual summit on climate change this week.

Mr Suga also said that Mr Biden expressed his support for the Tokyo Olympics to be held in July.

The Chinese Embassy in the US expressed "firm opposition" to the US-Japan statement, saying such comments had "completely gone beyond the scope of the normal development of bilateral relations". It added that the comments harmed the interests of third parties, mutual understanding and trust between regional countries, as well as peace and stability in the Asia-Pacific.

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