US Secretary of State Hillary Clinton issued a veiled warning to China not to challenge Japan's control of disputed islands as Tokyo's new government vowed not to aggravate tensions.
Foreign Minister Fumio Kishida met with Clinton on the first trip by a top Japanese official since Japan's conservatives returned to power last month. Clinton announced that Prime Minister Shinzo Abe would visit in February.
Amid signs that China is testing control control over virtually uninhabited islands in the East China Sea, Clinton said the area was under Japan's control and hence protected under a US security treaty with Tokyo.
"We oppose any unilateral actions that would seek to undermine Japanese administration," Clinton told a joint news conference with Kishida.
Clinton did not mention Beijing directly in the warning, but said: "We want to see China and Japan resolve this matter peacefully through dialogue."
"We do not want to see any action taken by anyone that could raise tensions or result in miscalculation that would undermine the peace, security and economic growth in this region," she said.
The United States insists it is neutral on the ultimate sovereignty of the islands -- known as the Senkaku in Japanese and the Diaoyu in Chinese -- but that they are under the de facto administration of Japan.
China has repeatedly criticized the US position. Chinese surveillance ships and state-owned planes have increasingly neared the area, in what some see as a bid by Beijing to contest the notion that Japan holds effective control.
"The frequency and scale of their provocations have drastically increased," Japanese foreign ministry spokesman Masaru Sato told reporters in Washington.
"The Chinese are trying to change the existing order by coercion or intimidation," he said.
Abe has been known throughout his career as a hawk on national security. But Kishida took a measured tone on China while in Washington, describing the relationship with Beijing as "one of the most important" for Japan.
"While Japan will not concede and will uphold our fundamental positions that the Senkaku islands are an inherent territory of Japan, we intend to respond calmly so as not to provoke China," Kishida said.
Kishida welcomed Clinton's support, saying that the statement on the security treaty "will go against any unilateral action that would infringe upon the administration rights of Japan."
US officials and pundits have largely welcomed the return of the Liberal Democratic Party, believing that Abe's firm positions and pledges to boost military spending will deter confrontational moves by Beijing.
However, Abe in the past has made controversial statements on Japan's wartime history, leading to fears that a loose comment could set off new tensions at a time that new leaders are also taking charge in China and South Korea.
Clinton said US officials "applaud the early steps" taken by Abe and hoped that new leaders in Japan and China would "get off to a good start."
Separately, Clinton said the United States and Japan wanted "strong action" at the UN Security Council on North Korea, which put a satellite into orbit last month in a launch the two allies fear could bolster Pyongyang's missile capabilities.
Diplomats at the United Nations said the United States and China, North Korea's main ally, had reached a compromise under which the Security Council would expand existing sanctions against Pyongyang.
The talks between Clinton and Kishida also focused on the hostage crisis in Algeria, with the two diplomats pressing the North African nation to release more information about a massive kidnapping at a desert gas field.
Addressing one point of friction, Kishida promised that Japan would sign the Hague treaty on child abductions. Hundreds of US parents have complained that they have no recourse if ex-partners take their children to Japan.
A previous left-leaning government had committed but not taken action on joining the Hague convention, which requires the return of wrongfully held children to the nations where they usually live.