Vice President Biden said Tuesday that the United States is “deeply concerned” about China’s establishment of an air defense zone over disputed islands in the East China Sea, a message aimed at reassuring U.S. allies while leaving negotiating room as he heads to Beijing.

Biden blamed China for raising tensions with Japan and South Korea, which he said would “increase the risk of accidents and miscalculation” in the wide flight path above the disputed islands, known as the Senkaku in Japanese and the Diaoyu in Chinese. But he stopped short of demanding that Beijing withdraw its declaration.

“We, the United States, are deeply concerned by the attempt to change the status quo in the East China Sea,” Biden said during an appearance with Japanese Prime Minister Shinzo Abe after they met for talks about security and economic matters.

Biden’s remarks, which echoed statements he made in a written interview with the Asahi Shimbun newspaper this week, were his first public comments on the dispute since arriving in Japan, the initial stop in a week-long trip to northeast Asia. The Obama administration hopes the trip will ease tensions as it seeks to refocus its foreign policy agenda on the fast-growing region.

The United States and Japan have continued to make military flights through the air defense zone in defiance of China’s declaration. But reports that the Federal Aviation Administration had told U.S. commercial airlines that they should comply with China’s demand for flight information before entering the zone have led some in Japan to question the Obama administration’s position.

Biden pledged to Abe that he would raise U.S. concerns with Chinese leaders, including President Xi Jinping, in Beijing during meetings scheduled for Wednesday and Thursday. He finishes his trip in Seoul before returning to Washington on Saturday.

“The United States has an interest in lowering tension in this vital region,” Biden said. He said the conflict has underlined the need to establish a “crisis management” protocol between Tokyo and Beijing, and improve communication between the two countries.

Abe said that he and Biden had “confirmed that we should not tolerate this attempt by China to change the status quo unilaterally by force. We will work closely dealing with the situation.”

Last month, China declared that it had establised an “air defense identification zone” above the islands, which have long been administered by Japan. The move immediately drew denunciations from the Japanese and objections from Obama administration officials, including Defense Secretary Chuck Hagel and Secretary of State John F. Kerry.

The FAA advised U.S. airline flights heading through the zone to file flight plans with the Chinese out of an abundance of caution, U.S. officials said.They described the recommendation as in line with standard guidelines for air defense zones around the world and as not a contradiction of the administration’s position.

Japanese officials ordered that country’s carriers to proceed as they had before China’s declaration. Some media reports in Japan speculated that Biden and Abe would agree on a written agreement or statement calling on China to withdraw its declaration, but Biden aides said such an agreement was never under consideration.

The aides said the White House thinks that China’s act was “provocative” and that China is to blame for initiating the standoff. They said Biden will ask China to exercise restraint in enforcing the air defense zone and to avoid creating such zones in other places — such as the South China Sea — without first discussing the move with countries that might be affected.

U.S. officials consider it highly unlikely that China would agree to withdraw its air defense zone. Biden’s message was designed to give U.S. negotiators room to persuade the Chinese to refrain from using aggressive military actions or inflammatory rhetoric to enforce its declaration, officials said. Taking a more strident tone might have angered the Chinese, officials said, making a diplomatic solution less likely.

“The aim is being 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,” said one senior administration official, who spoke on condition of anonymity to discuss private talks.

“We’ve constantly said relations with China are a balance of cooperation and competition. 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,” the official said.

Christopher K. Johnson, a China analyst at the Center for Strategic and International Studies, said the Obama administration’s message to China has been confusing. He pointed to State Department spokeswoman Jen Psaki’s statement this week calling on China to “rescind” some elements of the air defense zone.

“That does not seem to sync with the VP’s milder comments today emphasizing crisis management and confidence-building measures, with no mention of ‘rescinding’ anything related to the zone,” said Johnson, who was in Beijing for a conference. “This is sure to be very confusing for the Chinese, as they may be uncertain about what to expect.”

Administration aides said Abe accepted Biden’s position on the air defense zone. The aides emphasized that most of the two men’s discussions focused on other matters, including the final negotiations on the Trans-Pacific Partnership that the administration hopes to wrap up this year. The 12-nation trade pact includes Japan and Korea, but not China.

During a working dinner after their meetings, U.S. and Japanese officials had a long discussion about Iran, with the Americans aiming to encourage the Japanese, who have a better relationship with the Iranian regime, to help informally in negotiations over the country’s nuclear program, officials said.

Concluding his remarks, Biden cited his father’s expression that “the only conflict worse than an intended one is an unintended one.” Biden added, “The prospect of miscalculation is too high.”

When asked, officials noted that Biden’s jet, Air Force Two, would not be flying through the disputed flight path, which is south of the direct route from Tokyo to Beijing and Seoul.