The death toll from a 6.9-magnitude quake that hit the India-Nepal border has risen to 83, with much of the worst-affected area cut off by landslides.
At least 50 people have been killed in India's north-eastern state of Sikkim following the quake on Sunday.
Building collapses and landslides claimed another 18 lives in adjoining Indian states, Reuters reports.
Police said eight people were killed in Nepal, and China's official Xinhua news agency reported seven dead in southern Tibet.
Rescue teams heading to the mountainous area on Sikkim face a difficult task with cracked roads blocked by falling rocks and mud.
Thousands of troops have been deployed to dig through mudslides and clear away rubble in an effort to reach cut-off villages.
Hundreds of people spent a second night in the open as aftershocks continued, the BBC reports.
In the immediate aftermath of the quake heavy rains and landslides held up the relief effort. But a break in the poor weather allowed army helicopters to drop food supplies and transport medical teams to some affected areas.
Nevertheless, officials say the biggest challenge is reaching those villages in the most isolated areas of the mountainous state, amid fears that people may still be trapped under debris.
Explosives used on blocked roads
Convoys of vehicles left the state capital, Gangtok, on Tuesday morning but the AFP news agency says progress has been tortuously slow along precarious, badly damaged roads.
Troops and roadworkers have managed to restore the main highway linking Sikkim with the rest of India, but elsewhere they were using explosives to try and force their way through blocked roads.
Just over the border in Tibet's Yadong county, the quake caused hundreds of landslides, disrupting traffic, telecommunications, power and water supplies.