A tropical storm was forecast to bring heavy rain and strong winds to Okinawa and the Amami Islands on Saturday and Sunday, the Meteorological Agency said, adding that it could approach Kyushu early next week.

Tropical Storm Aere, referred to by Japan's weather agency as Typhoon No. 4, was south of Okinawa as of Friday evening and moving north at 15 kph. It carried winds near its center of 66 kph and maximum gusts of up to 90 kph. The wind speeds are expected to increase slightly as the storm moves northwest toward Okinawa.

The agency warned of the risk of landslides, flooding and high waves across wide areas, adding that Okinawa could see severe wind gusts, thunderstorms and tornadoes.

Separately, Severe Tropical Storm Chaba was expected to strengthen into a typhoon on its approach to mainland China, with a possible landfall on Sunday.