TOKYO, June 7 (Xinhua) -- Parts of western Japan were inundated by torrential rain from early Friday, with hundreds of people forced to evacuate and transportation services widely disrupted in the affected areas.

The Japan Meteorological Agency (JMA) said that warm, humid air moving toward a low-pressure system is causing very unstable atmospheric conditions on the Pacific coast of western and central Japan.

According to local media reports, 775 people were forced to escape to shelters as of 10 a.m. local time Friday in Hiroshima Prefecture, following level 4 out of 5 evacuation orders being issued, owing to the potential of flooding and mudslides in the region caused by downpours.

Similar warnings were issued in Yamaguchi and Ehime prefectures, where residents were also urged to seek shelter away from the downpours and potential floods and mudslides.

In contrast to last July when some 200 people lost their lives as a result of torrential rain, there have been no reports of injuries as a result of the deluge, thus far, according to local officials in the hardest-hit regions.

Rainfall in the 12-hour period through Friday morning exceeded 200 mm in Umaji village in Kochi Prefecture, the JMA said, while in the town of Taragi in Kumamoto Prefecture, 170 mm of rain was recorded.

In hard-hit Hiroshima, transportation networks were severely disrupted, with JR Sanyo Line services suspended in the early morning due to parts of the tracks being flooded.

The suspension affected around 15,000 people as 23 trains along the service were either suspended or severely delayed, said West Japan Railway Co.

Also in the region, Sanyo Shinkansen bullet train services and some smaller JR and private train lines were also temporarily suspended, wreaking havoc on commuters trying to get to work, as well as those looking to travel further afield by bullet train.

Looking ahead, the JMA said it forecasts 200 mm of rain in the Shikoku region and 120 mm in the southern Kyushu, Kinki and Tokai regions in the 24-hours through 6 a.m. local time on Saturday.

The agency declared that rainy season has started across wide swathes of eastern, central and northeastern Japan on Friday.

The JMA previously said that in Okinawa, the Amami region in Kagoshima Prefecture and southern Kyushu rainy season had already officially begun.