Nepali authorities on Sunday evacuated villages and towns along a mountain river in the northwest after it was blocked by a landslide overnight.

The landslide, thought to have been triggered by recent earthquakes, carried mud and rocks into the Kali Gandaki river at the village of Ramhe in Myagdi district, about 140 km (90 miles) northwest of the capital, Kathmandu.

The blockage has caused water levels to rise rapidly to form a large lake that could unleash devastating floods if its natural dam breaks.

Residents at risk

Officials say that flooding could reach as far as India if the blockage were to give way.

They said they had no reports of casualties despite witnesses saying about two dozen houses had been swept away.

In 2002, the nearby Seti River burst through a blockage caused by an avalanche, inundating villages along its banks and killing dozens of people.

Earthquake after-effects

Soldiers and police officers have been sent to monitor the river, and Prime Minister Sushil Koirala has ordered security personnel to try and clear the blockage, his office said.

Repeated aftershocks in the wake of two deadly earthquakes on April 25 and May 12 have loosened soil and caused a number of landslides in the country in the past weeks.

Nepal is still reeling from the disasters, with more than 8,600 people killed in the quakes, while thousands have been left in need of food, clean water and shelter.

tj/bw (Reuters, dpa, AFP)