Rescue teams battled landslides and heavy rains Monday after an earthquake rocked a vast swathe of northeast India and Himalayan states, killing at least 45 people in India, Nepal and Tibet.
The epicentre of Sunday's 6.9-magnitude earthquake was in a remote region on the border between India's Sikkim state and Nepal, and there were fears the toll could rise as reports filter in from isolated town and villages.
Tremors were felt more than 1,000 kilometres (600 miles) away in New Delhi to the west, and in Bangladesh to the east.
In Nepal, police said a motorcyclist and his eight-year-old daughter were among three killed when a wall crumbled at the British embassy compound in the capital Kathmandu, 270 kilometres west of the epicentre.
Three others were killed in separate incidents in eastern Nepal, national police spokesman Binod Singh told AFP.
A budget debate in Nepal's parliament stopped for 15 minutes when lawmakers leapt to their feet and fled the chamber as the entire building shook.
At least 60 people were injured by mudslides, falling debris and collapsing buildings in Gangtok, the state capital of Sikkim, where thousands spent the night in the streets after two large aftershocks sparked further panic.
"We all ran out of our houses, some even jumped out of their windows. You can see some buildings that have developed cracks," said Gangtok resident C.K. Dahal.
The quake downed power lines, blacking out Gangtok and most of Sikkim, further hampering rescue efforts as telephone land lines were interrupted and panicked mobile users swamped local networks.
"The biggest challenge now is to get the rescue teams to the affected areas," said Sikkim Information Minister C.B. Karki.
G. Anandan, chief of the central emergency control room in Gangtok, said five people had been killed in the city, and another 18 had died in building collapses and landslides in outlying towns and villages.
"There's a good chance the death toll could rise as rescue teams begin to access the more remote areas," Anandan told AFP.
Air force planes carrying rescue teams from Delhi were despatched to Bagdogra airport, around 125 kilometres south of Gangtok.
Torrential monsoon downpours grounded all helicopter flights, and the rains and landslides had washed away or blocked numerous sections of the only highway to Gangtok.
"Our rescue teams are stuck in that corridor," said National Disaster Response Force spokesman Surendra Ahlawat. "The conditions are terrible, but road crews are doing their best."
The quake was felt across a wide region including the Himalayan kingdom of Bhutan after it struck at about 6:10pm (1240 GMT) on Sunday, according to the US Geological Survey.
Its epicentre was just over 60 kilometres northwest of Gangtok, at a relatively shallow depth of 19.7 kilometres.
The Press Trust of India said that police rescued 15 foreign tourists in the north of Sikkim, a popular destination for trekkers.
Nine other people died in India, including one killed in a stampede by panicked residents in Bihar state and four who were buried when a house fell down near Darjeeling.
China's official Xinhua news agency said seven people had been killed in southern Tibet, near the border with Sikkim.
Strong tremors were felt in Guwahati, the main city in India's Assam state, some 600 kilometres away, sending people running into the streets.
"Our apartment block was literally swaying," said housewife Anamika Das.
In Kathmandu, traffic came to a standstill as hotels and bars were evacuated. Hundreds of anxious tourists and residents waited for news in car parks and on the streets as the seasonal monsoon rain lashed down.
India's seven northeastern states, joined to the rest of the country by a narrow sliver of land known as the "chicken's neck," are located in an area of frequent seismic activity.