U.S. Ambassador to Japan nominee Rahm Emanuel on Wednesday vowed to enhance bilateral ties as China seeks to "conquer through division," while welcoming a potential increase in Japan's defense spending.

Calling the bilateral partnership the "cornerstone of peace and prosperity in a free and open Indo-Pacific," Emanuel, who served as a top aide to former President Barack Obama, told the Senate Foreign Relations Committee, "If confirmed, my top priority will be to deepen these ties."

"China aims to conquer through division. America's strategy is security through unity. That regional unity is built on the shoulders of the U.S.-Japan alliance," the 61-year-old added.