The United States cannot be successful in the Indo-Pacific unless it works closely with Japan, Kurt Campbell, nominated by President Joe Biden to be the second-highest ranking official at the State Department, said Thursday.

"Our most important ally and partner on the global stage today might be Japan," Campbell said while testifying at a Senate Foreign Relations Committee hearing.

In an era of China's rise, Campbell stressed that strengthening security and economic ties with Tokyo and other partners is central to U.S. national and strategic interests.