New Delhi, Oct. 7 -- Lt. Gen. Benjamin Watson, commander of III Marine Expeditionary Force, said in a letter posted on social media Tuesday that episodes like these "demand we pause for reflection" and that serving on the Japanese island "comes with responsibility."

The arrest of the Marine has renewed protests against the heavy American military presence on the southern island and the rise in military-related crime. The killing could also complicate Prime Minister Sanae Takaichi's push to strengthen the Japanese military on Okinawa and to work more closely with the U.S. military to deter China in the region.

"We live, work, and socialize alongside the people of Okinawa; their home is our home," Watson wrote. "Every interaction with our...