Japan complained to Beijing on Wednesday that a Chinese military helicopter flew close to a Maritime Self-Defense Force vessel in waters off Okinawa — the second such incident this month.

The helicopter came within about 90 meters of the MSDF vessel, which was monitoring Chinese military activities, a Defense Ministry spokesman said. He declined to be named, citing department policies.

The Chinese helicopter flew in a circle twice near the MSDF vessel, which was around 500 km south of Okinawa, he said.