Nepal has declared three days of mourning for the victims of Saturday's earthquake in which more than 5,000 people are now known to have died.
Prime Minister Sushil Koirala says the government is doing all it can but is overwhelmed by the scale of the catastrophe.
Rescuers are still struggling to bring aid to remote Himalayan areas.
Heavy rain is worsening the plight of hundreds of thousands of people camped out in the open. The UN estimates that eight million people in 39 districts have been affected by the 7.8-magnitude quake - more than a quarter of the population.
More than 10,000 people have been injured.
Among the dead are 18 climbers who were at Mount Everest base camp when it was hit by an avalanche triggered by the quake.