Tokyo, Jun 3 (IANS): Wide swathes of Japan are being hit by heavy downpours, especially in western regions, owing to bands of thick thunderclouds formed due to Tropical Storm Mawar's presence in the Pacific, weather officials said.

The Japan Meteorological Agency (JMA) on Friday said that as well as causing torrential rain in Kochi, Wakayama, and Nara prefectures in western Japan, the band of thunderclouds was also causing heavy rain in the Tokai and Kanto-koshin region, which includes Tokyo.

The agency said conditions in the Kanto-koshin region could worsen on Saturday as more thunderclouds are expected to form, Xinhua news agency reported.

The weather agency also said the bands of thick thunderclouds would affect regions for a protracted period from western to eastern Japan as the clouds and moist air from Tropical Storm Mawar hit a weather front.

Heavy rain advisories were issued by the JMA on Friday for Kochi, Wakayama, and Nara prefectures, warning of possible landslides and floods in low-lying areas, as well as swollen rivers breaching their banks.

Weather officials said Mawar is currently moving eastward on waters near Amami Island in Kagoshima prefecture.

Along with the Okinawa and Amami regions, weather officials said that areas in Kyushu are now within the storm's zone of strong winds, and have warned residents to be vigilant of powerful wind gusts, floods, landslides, and lightning.