After visiting Beijing and Seoul, U.S. Defense Secretary James Mattis arrived in Tokyo on Friday to reaffirm Washington's commitment to the defense of Japan.

He also agreed with Defense Minister Itsunori Onodera to strive for the removal of all of North Korea's nuclear weapons and ballistic missiles, including those with shorter ranges that can target Japan but not the U.S. mainland.

The secretary was apparently trying to ease simmering concerns in Japan that U.S. President Donald Trump may strike a half-way compromise with the North in negotiations to abolish its nuclear and ballistic missile programs. Tokyo is also worried about the U.S. commitment to defending the region, with Trump having abruptly announced after his June 12 summit with North Korean leader Kim Jong Un in Singapore plans to halt large-scale military exercises on the Korean Peninsula.