Japanese Prime Minister Fumio Kishida told U.S. lawmakers Thursday the United States does not have to confront serious global challenges alone, saying Tokyo is upgrading its military capabilities to support its ally.

In a joint meeting of the U.S. Congress, Kishida urged the U.S. to continue its role upholding the international order and addressed skepticism among some Republican lawmakers about continuing aid to Ukraine.

“The leadership of the United States is indispensable. Without U.S. support, how long before the hopes of Ukraine would collapse under the onslaught from Moscow?” Kishida asked during his speech.

Japan has provided $12 billion in aid to Ukraine, including anti-drone detection systems. Kishida also hosted a conference for Ukraine’s economic growth.

U.S. lawmakers in support of aid to Ukraine have suggested a failure to confront Russia will send a message to China that it can expand its own ambitions in Taiwan.

Biden hosts Kishida in official visit as US, Japan bolster defense ties