Japan's coast guard has said that two Chinese government ships which entered Japan's territorial waters near the Senkaku Islands in the East China Sea on Thursday both left on Sunday morning.The vessels navigated in waters off Japan's Okinawa Prefecture for 72 hours and 45 minutes.That marks the longest-ever continued intrusion of its kind since the Japanese government purchased some of the Senkakus from a private Japanese owner in 2012.The Chinese ships' intrusion into Japan's territorial waters broke the previous record of a similar incident that lasted for 64 hours and 17 minutes between July 5 and 7 of this year.The Japanese coast guard remained on alert after warning the vessels against re-entering Japan's waters."