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.

“Across the region, America’s closest regional allies like Australia and South Korea understand the PRC (People’s Republic of China) poses the greatest long-term strategic threat to a free and open Indo-Pacific. But they also understand that what happens in Europe or the Middle East in the near term matters an awful lot to Asia,” Senate Minority Leader Mitch McConnell said in a statement following Kishida’s address.

A $96 billion supplemental security package providing aid to Ukraine and Indo-Pacific countries confronting Chinese aggression, passed the Democratic-majority Senate but has been stalled for months in the House of Representatives, which is narrowly controlled by Republicans.

Kishida’s plea to U.S. lawmakers comes as part of a three-day state visit to Washington. On Wednesday, Kishida met with President Joe Biden and announced a number of new defense partnerships between the two countries.

The decades-long alliance between the U.S. and Japan is widely seen as key to countering Chinese aggression. Kishida acknowledged the partnership with the U.S. and broader regional alliances Thursday.

“Without the presence of the United States, how long before the Indo-Pacific would face even harsher realities?” Kishida said in his address. “Our alliance serves as a force multiplier and together with these like-minded countries, we are working to realize a free and open Indo-Pacific,” he said.