US President Joe Biden stated to key Asian allies that the world is now "navigating a dark time in our shared history" following Russia's invasion Ukraine.
He said that the war is now a "global problem" which underlines the importance of defending international peace and order.
Fumio Kishida, the Japanese Prime Minister, echoed his remarks and said that Asia should not be subject to a similar invasion.
In Tokyo, Mr Biden met with leaders from Australia, Japan and India during his first trip to Asia as President.
The Quad, a group of four countries that is also known as China and Russia, discussed economic and security concerns. They also debated differences about the Russian invasion.
Biden's remarks came just days after he warned China about its "flirting in danger" over Taiwan. He also promised to defend Taiwan militarily if China attacked. This seems to be contrary to a long-standing US policy.
Later, it was reported that Russian and Chinese warplanes approached Japanese airspace in the course of a joint military patrol. Tokyo announced that it had scrambled its jets to respond.
Russian officials claimed that the annual military exercise involved the flight above the Sea of Japan, East China Sea and Sea of Japan.
A news conference was held by Mr Kishida, who said that the planning of the exercise to coincide today's summit was "provocative".
In his opening remarks to Tuesday's summit, Biden stated that their meeting was about "democracies against autocracies" and that they must deliver.
He stated that the Ukraine war "is going to impact all parts of world" because Russia's blockade on Ukraine grain exports has exacerbated a global food shortage.
Biden stated that the US would cooperate with allies in leading the global response. He reiterated their commitment to defend sovereignty and international order "regardless" of the violations in the world and said they will remain a "strong, enduring partner" for the Indo-Pacific region.
Reporters were informed by Mr Kishida after their meeting that all four countries, including India, agreed on the importance and sovereignty of the rule and law and that unilateral attempts to alter the status quo through force will not be tolerated.
India is the Quad's only member who has not directly criticised Russia for the invasion. In what seemed to be a concession made to Delhi, no mention was made of Russia in the joint statement at the conclusion of the talks.
The Quad nations did not mention China, however, they announced a new maritime surveillance initiative. This will increase surveillance of Chinese activities in the region. They also plan to invest at least $50bn (PS40bn), on infrastructure projects, and investment, over the next five year.
