China's ambassador to Japan says both nations should calmly handle the alleged intrusion by a Chinese sub into Japanese waters.
During a speech in the Wakayama Prefecture on Saturday, Ambassador Wang Yi acknowledged the differences between his country and Japan, but said both sides should approach the matter with mutual respect and calm.
Japan mobilized its navy Wednesday after a submarine was spotted near the southern island of Okinawa.
Japan's Foreign Ministry summoned Chinese diplomat Chen Yonghua Friday to lodge a protest and demand an official apology. But official Chinese state media have not reported the incident.