Landing in Japan on the first stop of his marathon five-nation tour of Asia, U.S. President Donald Trump on Sunday called the nation a "treasured partner" and "crucial ally" of the United States while asserting that "no dictator" and "no regime" should ever underestimate America — a not-so-veiled rebuke of nuclear-armed North Korea.

After paying a solemn visit to Pearl Harbor and the USS Arizona Memorial in Hawaii on Friday, Trump on Sunday marked the start of his trip to Asia by disembarking from Air Force One at the U.S. Air Force's Yokota Air Base in western Tokyo. Cheers erupted as he appeared on stage with his wife, first lady Melania Trump, prompting thousands of U.S. military personnel there to welcome the pair with enthusiastic chants of "USA! USA! USA!"

"Japan is a treasured partner and crucial ally of the Unites States," Trump told a packed aircraft hangar after changing into a bomber jacket. "Today we thank them for decades of wonderful friendship between our two nations."