World Bulletin / News Desk

The death toll from record rains that have devastated parts of Japan rose Sunday to at least 57, officials said, as rescue workers and troops struggled in the mud and water to save lives.

Prime Minister Shinzo Abe warned of a "race against time" to rescue flood victims, some of whom have resorted to tweeting desperate messages seeking help from emergency services.

The torrential downpours have caused flash flooding and landslides across central and western Japan, with some villages engulfed by rising waters, and trapped residents taking shelter on their rooftops as floods swirl below.

Over two million people have been told to evacuate, but the orders are not mandatory and many remained at home, becoming trapped by rapidly rising water or sudden landslides.

The meteorological agency issued new alerts on Sunday, while lifting the warning level in other regions where rain was subsiding.

But it also cautioned residents that even where downpours were over, the heavy rains had loosened earth -- meaning the risk of landslides remained high.