Japan's Kyodo news says Chinese patrol ships entered Japanese territorial waters on Friday morning near the recently nationalized Senkaku islands.

Kyodo reported that this is the first time Chinese ships have trespassed in waters near the islands since Tokyo nationalized the territory on Tuesday.

The news agency said Japan’s Coast Guard said two surveillance ships entered Japanese territorial waters near Taisho Island around 6:20 a.m. on Friday and left at around 7:50 a.m.

Japan’s Coast Guard says it ordered the ships to leave. The Chinese surveillance ships responded that the islands, which are called Diaoyu in Chinese, are Chinese territory and their surveillance activities were legitimate.

Japan’s foreign ministry summoned China’s ambassador to Japan in protest of the reported trespassing.