Biden and Japanese PM pledge united front against China
US President Joe Biden and Japanese Prime Minister Fumio Kishida have touted increased joint military co-operation and a new missile defence system, strengthening their alliance with an eye on actions by China and Russia.
"This is the most significant upgrade in our alliance since it was first established," Biden said at a joint White House news conference with Kishida, after about two hours of talks that focused on the Pacific, Ukraine and the Gaza conflict.
The US president said the two nations' forces will co-operate on a joint command structure and, along with Australia, develop a new air missile defence network.
Kishida said the two leaders also discussed tense relations between Taiwan and China, and pledged to uphold international order based on the rule of law.
"Unilateral attempts to change status quo by force or coercion is absolutely unacceptable, wherever it may be," Kishida said.
The US and Japan will continue to respond to such actions, including challenges from China, he said.
"Regarding Russia's aggression of Ukraine ... Ukraine today may be east Asia tomorrow," Kishida said.
Biden also vowed to keep open lines of communication with China and said the US-Japan alliance was defensive in nature. He spoke to Chinese President Xi Jinping last week.
The announcements from Biden and Kishida brought the two old World War II enemies into the closest collaboration they have had since they became allies decades ago.
The two leaders also announced that Japanese astronauts will participate in NASA moon missions.
Japan, the US' largest source of foreign direct investment, is taking on a stepped-up global role after a series of security law changes in the past decade that have transformed its pacifist constitution.
Kishida will address the US Congress on Thursday and join Biden and Philippines President Ferdinand Marcos Jr for a meeting expected to focus on South China Sea incursions by China's navy.
Overall, the US and Japan have hammered out about 70 agreements on defence co-operation, including moves to upgrade the US military command structure in Japan to make it better able to work with Japanese forces in a crisis.
The meeting comes as China steps up pressure on the Philippines in the South China Sea over area it claims but international law says belongs to the Philippines.
China is attempting to isolate Japan and the Philippines, a US official said.
By meeting the leaders of those two countries this week in Washington DC, Biden is aiming to "flip the script and isolate China".
Fitch cut its outlook on China's sovereign credit rating to negative on Wednesday, citing risks to public finances as the economy faces increasing uncertainty in its shift to new growth models.
On Thursday, Biden will hold a bilateral meeting with Marcos, whom he welcomed in Washington DC just last year, before the pair join Kishida for a trilateral summit.
The visit may give a political boost to Kishida, whose popularity has waned at home.
He is being greeted with great fanfare, with Japanese flags on display throughout the US capital.
Overshadowing the visit is a controversy over the planned $US15 billion ($A23 billion) acquisition of steel maker US Steel by Japan's Nippon Steel, a deal some say is "on life support" after criticism by Biden and former president Donald Trump, his rival in November's US election.
Kishida, asked about the deal, said he hoped discussions about it would bear fruit.
"We wish to cement this win-win relationship," he said.
Biden said he stood by his commitment to union workers on the issue.
