HONG KONG - International aid groups and governments escalated efforts to dispatch rescuers and supplies to Nepal yesterday, but severed communications and landslides posed formidable challenges to the relief effort.

As the death toll passed 2,300, the United States, together with several European and Asian nations, including Singapore, sent emergency crews to reinforce those scrambling to find survivors in the devastated capital, Kathmandu, and rural areas cut off by blocked roads and patchy phone networks.

"Roads have been damaged or blocked by landslides and communication lines are down, preventing us from reaching local Red Cross branches to get accurate information," said Mr Jagan Chapagain, Asia-Pacific director of the International Federation of the Red Cross and Red Crescent Societies (IFRC).

The IFRC said it was extremely concerned about the fate of villages near the quake's epicentre, some 80km from Kathmandu.

"We anticipate that there will be considerable destruction and loss of life," Mr Chapagain said.

Other aid organisations responding to the emergency also struggled to assess requirements across the country and spoke of the fearsome effects of the quake.

"We witnessed terrible scenes of destruction - hospitals were evacuated, with patients being treated on the ground outside, homes and buildings demolished and some roads cracked wide open," said Ms Eleanor Trinchera, Caritas Australia programme coordinator for Nepal.

Survivors slept in the open in Kathmandu overnight, braving the cold for fear of being crushed by the teetering ruins of buildings. Hundreds of structures, including a landmark tower, collapsed on Saturday when the 7.8-magnitude quake struck.

Meanwhile, snowfalls on Saturday thwarted efforts to airlift survivors from an avalanche that hit part of Everest base camp, killing at least 18 people, although helicopters started landing yesterday.

US Secretary of State John Kerry said Washington was working closely with the Nepal government to provide assistance.

"To the people in Nepal and the region affected by this tragedy, we send our heartfelt sympathies," he said.

A US disaster response team was en route to Nepal and an initial US$1 million (S$1.3 million) in aid to address immediate needs had been authorised, the US Agency for International Development said.

Neighbouring India dispatched 13 military aircraft to help with the rescue and relief efforts as it emerged that 62 people had died there from the effects of the massive quake.

China said it had dispatched a 62-member search and rescue team with sniffer dogs and had started work on an emergency humanitarian aid plan, the official Xinhua news agency reported.

The European Union said its humanitarian experts were heading to the crisis areas. Germany, Britain and Spain also pledged support and assistance, with Norway promising to provide 30 million krone (S$5.1 million) in humanitarian aid.

AGENCE FRANCE-PRESSE