A Chinese naval intelligence ship briefly entered Japan's territorial waters on Wednesday morning, a top official said.

Deputy Chief Cabinet Secretary Hiroshige Seko said a Japanese Maritime Self-Defense Force plane spotted the Chinese naval ship in Japanese territorial waters west of Kuchinoerabu Island in southern Japan before dawn. Seko said the ship sailed out of the territorial waters about 90 minutes later.

Seko said an official from the Foreign Ministry's Asian and Oceanian Affairs Bureau expressed concern to an assistant ambassador of the Chinese Embassy in Tokyo about the Chinese naval activity. The incident comes after a Chinese naval ship sailed near the disputed Senkaku islands last week.