Four China Coast Guard vessels entered Japanese waters around the disputed Senkaku Islands in the East China Sea on Monday, the Japan Coast Guard said. 
The ships were spotted in territorial waters around the group of uninhabited islets, the first intrusion since Nov. 14. 
The islands are controlled by Japan and claimed by China, which calls them Diaoyu, according to (Kyodo) news agency A patrol boat of the Japan Coast Guard issued a warning calling on the Chinese ships to leave Japanese territory.

Source: QNA