US Secretary of State Antony Blinken has warned China against using "coercion and aggression" as he sought to use his first trip abroad to shore up Asian alliances in the face of growing assertiveness by Beijing.
China's extensive territorial claims in the East and South China Seas have become a priority issue in an increasingly testy Sino-US relationship and are an important security concern for Japan.
"We will push back if necessary when China uses coercion and aggression to get its way," Blinken said on Tuesday.
Blinken came to Tokyo with Defence Secretary Lloyd Austin in the first overseas visit by top cabinet members of President Joe Biden's administration. It follows last week's summit of the leaders of the US, Japan, Australia and India - the Quad alliance.
Washington has denounced what it called Beijing's attempts to bully neighbours with competing interests. China has repeatedly denounced what it called US efforts to foment unrest in the region and interfere in what it regards as its internal affairs.
In the statement issued with their Japanese counterparts, Blinken and Austin "acknowledged that China's behaviour, where inconsistent with the existing international order, presents political, economic, military and technological challenges to the Alliance and to the international community."
The two countries "committed to opposing coercion and destabilising behaviour towards others in the region, which undermines the rules-based international system."
The meeting was held in the "2+2" format with Japanese Foreign Minister Toshimitsu Motegi and Defense Minister Nobuo Kishi as hosts.
North Korea was also in sharp focus after the White House said Pyongyang had so far rebuffed efforts to engage in dialogue. North Korea, which has pursued nuclear and missile programs in defiance of UN Security Council resolutions, warned the new US administration against "causing a stink" if it wants peace, North Korean state media reported on Tuesday.
Blinken said he wanted to work with Japan and allies on the denuclearisation of North Korea.
The ministers also discussed Washington's "unwavering commitment" to defend Japan in its dispute with China over islets in the East China Sea and repeated their opposition to China's "unlawful" maritime claims in the South China Sea.
The ministers also shared "serious concerns" over "disruptive developments" such as the law China passed in January allowing its coast guard to fire on foreign vessels.
China has sent coast guard vessels to chase away fishing vessels from other countries with which it has disputes in regional waters, sometimes resulting in their sinking.
Motegi said China-related issues took up the majority of his bilateral talks with Blinken and "expressed strong opposition to China's unilateral attempt to change the status quo in the East and South China Seas."
Other issues discussed on Tuesday included COVID-19 vaccines, semiconductor supply-chain security, the military coup in Myanmar and human rights in North Korea, as well as in Hong Kong and Xinjiang.
After the Seoul leg, Blinken will fly to Alaska, where he will be joined by national security adviser Jake Sullivan for their first in-person talks with Chinese counterparts.