Hundreds of Nepalis gathered Monday at the ruins of a 19th-century tower in Kathmandu to mark one month since a devastating earthquake killed more than 8,600 people in the Himalayan nation.

The quake, which was followed by a second major tremor on May 12, brought down buildings across the country including historic temples, monuments and the much-loved Dharahara tower as tourists and locals climbed its more than 200 steps.  

After the national anthem played on loudspeakers, crowds surrounded the crumbled tower and observed 56 seconds of silence at 11:56, the moment the 7.8-magnitude quake ripped through Nepal on April 25.

Nina Shrestha, a 23-year-old student carrying a small Nepali flag, said the nine-storey tower was "always the first thing" she looked for when flying into Kathmandu.

"Its collapse signifies the devastation our country has suffered," she told AFP.

The 50.5-metre (165-foot) high attraction -- which contained a spiral staircase and offered visitors panoramic views of the capital -- was reduced to just its base when the quake struck.

Ram Chandra Shrestha, who spent 12 years tending the garden in the tower complex, told AFP that "it is hard to look up and not see the tower, it sends a chill through my heart".

Those attending the ceremony, organised by young political party Bibeksheel Nepali, told of their despair not only of losing their homes to the quake but also their jobs, leaving them facing a bleak future.

Like thousands of others, 41-year-old Dil Maya Rai has been living in a tent since the massive quake.

"We can't find a room to rent and the carpet factory where I worked also collapsed in the quake," Rai told AFP.

"I don't know how we will get by," he said.

The twin quakes destroyed nearly half a million houses and left thousands in desperate need of food, clean water and shelter, with experts warning that the window to help victims is closing fast before monsoon rains arrive next month.

Elsewhere on Monday, officials said thousands of villagers have returned to their homes in the mountainous northwest after a river which was dammed by a landslide began flowing normally again.

The landslide late Saturday night had sent mud and rocks tumbling into the Kali Gandaki river in Myagdi district, creating a large artificial lake and sparking fears of flash flooding.