A family sits inside their makeshift shelter at an open ground after an earthquake in Kathmandu, Nepal April 26, 2015. [Photo/Agencies]

KATHMANDU - Thousands of desperate Nepalese huddled under tents and sought scarce food and medical supplies on Monday, two days after a massive quake killed more than 2,500 people, as overwhelmed authorities struggled to care for the wounded and homeless.

The sick and wounded lay out in the open in the capital, Kathmandu, unable to find beds in the devastated city's hospitals. Surgeons set up an operating theatre inside a tent in the grounds of Kathmandu Medical College.

"We are overwhelmed with rescue and assistance requests from all across the country," said Deepak Panda, a member of the country's disaster management.

Across Kathmandu and beyond, exhausted families whose homes were either flattened or at risk of collapse laid mattresses out on streets and erected tents to shelter from rain.

People queued for water dispensed from the back of trucks, while the few stores still open had next to nothing on their shelves. Crowds jostled for medicine at one pharmacy.

High in the Himalayas, hundreds of foreign and Nepalese climbers remained trapped after a huge avalanche ripped through a base camp for climbers, killing 17 people in the worst single disaster to hit Mount Everest.

A total of 3,218 people were confirmed killed in the 8.1 magnitude quake, making it the worst such disaster to hit Nepal since 1934 when 8,500 died. Thousands more were injured.

The toll is likely to climb as rescuers struggle to reach remote regions in the impoverished, mountainous country of 28 million people and as bodies buried under rubble are recovered.