India, Aug. 30 -- The water levels in the Bhotekoshi River rose again on Sunday, days after a devastating flash flood struck Nepal, authorities warned, urging residents and rescue personnel in flood-hit districts to remain alert.

The death toll from the August 26 flash floods crossed 700 on Sunday, while nearly 2,500 remain missing.

The disaster, believed to have been triggered by a collapse or avalanche of ice and rock near the Nepal-Tibet border, devastated towns and villages in central Nepal.

The Bhotekoshi River, which flows south from the Himalayan border region, carried the floodwaters downstream, sweeping away homes, vehicles, roads and bridges and damaging hydropower projects.

In a statement, the National Disaster Risk Reducti...