Tokyo, Jul 25 (IANS): Torrential rain lashed regions in northeastern Japan and triggered river flooding and landslides, prompting the weather agency to urge residents to remain alert with downpour warnings issued on Thursday.

The Japan Meteorological Agency (JMA) issued downpour warnings at the highest level for two municipalities in the northeastern prefecture of Yamagata, shortly after 1 p.m. local time, urging residents to take immediate action to protect their lives.

The agency later downgraded the highest-level heavy rain emergency warning for Sakata City and Yuza Town to a warning at 8:10 p.m. local time, noting the risk of rivers overflowing and flooding is still high, Xinhua news agency reported.

According to the JMA, more than 100 millimeters of rain fell in the two municipalities and their vicinities during an hour through 9:00 a.m. local time.

The agency said atmospheric conditions are very unstable in areas of the Tohoku region along the Sea of Japan, and torrential rain is falling in Yamagata and neighboring Akita Prefecture.

In Akita, a river in Yurihonjo City burst its banks in the early hours of Thursday, flooding houses. One person has gone missing following a landslide at a roadwork site in Yuzawa City, Kyodo News reported.

The unstable weather conditions are expected to continue through Friday, with warm, moist air flowing toward a rainy season front lingering over the country, the JMA said.