Thousands of people fled villages and towns along a mountain river in northwest Nepal after it was blocked by a landslide that could burst and cause flash floods, Sky News reported Tuesday.

The landslide created a dam and a lake two kilometres long on the Kaligandaki River,a government official said.

Residents living on the banks of the river were moved to higher grounds for fear the river could burst and send flash floods through the area north of Beni Bazaar, about 200km northwest of the capital, Kathmandu.

Soldiers and police officers were sent to monitor the river and help and warn the villagers.

Two powerful earthquakes devastated Nepal on April 25 and May 12, killing nearly 8,700 people and injuring 16,800 others.

The quakes and aftershocks also triggered many landslides in the Himalayan nation.