Heavy rain from Tropical Storm Khanun pounded southerwestern Japan on Wednesday as another storm approached from the east to possibly threaten Tokyo just as thousands of people prepare to travel during the peak summer holiday season.

Khanun could make landfall on the island of Kyushu, some 858 kilometers from Tokyo, on Thursday, but areas of the region have already been inundated with a whole month's worth of rainfall in the past week, the Meteorological Agency said.

The storm is currently in the sea south of Kyushu after wreaking havoc in the Okinawa region.