"We, the United States, are deeply concerned by the attempt to unilaterally change the status quo in the East China Sea," Biden said Tuesday in a joint appearance with Japanese Prime Minister Shinzo Abe in Tokyo after the two met in private. "This action has raised regional tensions and increased the risk of accidents and miscalculation."
Japan and China have disputed ownership of an island chain and the seas around it. China last week unilaterally decided to create an air defense identification zone, requiring airplanes to identify themselves. U.S. aircraft flew several times inside the ID zone in defiance.
Biden said the United States was monitoring the situation with its allies in Japan and South Korea, and said he assured Abe that "we will remain steadfast in our alliance commitments."
"The United States has an interest in the lowering of tensions in this vital region," Biden said. "This underscores the need for crisis management mechanisms and effective channels of communication between China and Japan to reduce the risk of escalation."
The vice president, who kicked off his Asia visit in Japan, said he would raise these concerns when he meets with Chinese leaders later this week.
"The prospect for [a] miscalculation [or a] mistake is too high," Biden said.
Abe said, through an interpreter, he and Biden confirmed "we should not tolerate the attempt by China to change status quo unilaterally by force, and we will continue to work closely in dealing with the situation based on [a] strong U.S.-Japan alliance."
"Above all, we reaffirmed that policies and measures, including those on operation of the self-defense forces and U.S. forces will not change, and that we will meet in close cooperation," Abe said. "We further agreed that we will not condone any action that could threaten [the] safety of civilian aircraft."
Speaking on background after Biden and Abe met, a senior U.S. official said a goal of Biden's meetings in Beijing is to be "clear and consistent with China and Chinese leaders about our alliance [with Japan and South Korea], the strength of our alliances and commitments, regarding behavior that is destabilizing."
"We've constantly said relations with China are a balance of cooperation and competition," the senior official said. "We need to grow the cooperative elements, but it's important that when we have disagreements with the Chinese to be clear about them and help them understand there will be a cost to their actions."
Biden said he and Abe also discussed the Trans-Pacific Partnership, a regional trade pact that covers 12 countries that account for about 40 percent of the world's gross domestic product.
"To state the obvious, for the countries involved, the decisions and the compromises that need to be made are very sensitive and very difficult," Biden said, noting the partnership would be "incredibly positive" for all countries involved.
"But the reward does not diminish the realization of how difficult the compromises ... [that] needed to be made are," Biden said. "We need a comprehensive agreement that involves longstanding differences between the United States and Japan, including issues like agriculture and automobiles. And it's difficult."
Abe said a political solution for the "difficult issues" of TPP participants as negotiations enter their final phase.
"I explained [to Biden] that Japan and the United States need to solve major pending issues through cooperation," Abe said, "and then should show a path toward conclusion of negotiation within this year."
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