KATHMANDU: A powerful earthquake struck Nepal on Saturday, killing at least 1,180 people across a swath of four countries as the violently shaking earth collapsed houses, leveled centuries-old temples and triggered avalanches on Mount Everest.

It was the worst tremor to hit the poor South Asian nation in over 80 years. At least 1,130 people were confirmed dead across Nepal, according to the police. Another 34 were killed in India, 12 in Tibet and two in Bangladesh. Two Chinese citizens died on the Nepal-China border. The death toll is almost certain to rise, said deputy Inspector General of Police Komal Singh Bam.

It was a few minutes before noon when the quake, with a preliminary magnitude of 7.8, began to rumble across the densely populated Kathmandu Valley, rippling through the capital Kathmandu and spreading in all directions — north toward the Himalayas and Tibet, south to the Indo-Gangetic plains, east toward the Brahmaputra delta of Bangladesh and west toward the historical city of Lahore in Pakistan.

Shrish Vaidya, a businessman, was with his family in his two-story house on the outskirts of Kathmandu, when the quake struck. “It is hard to describe. The house was shaking like crazy. We ran out and it seemed like the road was heaving up and down,” he said. “I don't remember anything like this before. Even my parents can't remember anything this bad.”

Officials said an avalanche had buried parts of Mount Everest's base camp in Nepal where hundreds of mountaineers have gathered at the start of the annual climbing season.

“An avalanche from Mt. Pumori has hit the base camp, burying a part of it, “Gyanendra Kumar Shrestha, an official in Nepal's tourism department, told AFP.

“We are trying to assess how many are injured. There might be over 1,000 people there right now, including foreign climbers and Nepalese supporting staff."

AFP Nepal bureau chief Ammu Kannampilly, on an assignment to Everest, was among those caught up in the chaos and reported that snowfall meant it was impossible for helicopters to reach the area.

Two experienced mountaineers said that panic erupted at base camp which was full of climbing teams and had been “severely damaged”, while one said the quake triggered a “huge avalanche”.

International aid groups rushed to respond Saturday to a massive earthquake in Nepal that claimed more than 1,000 lives as aftershocks and severed communications hampered rescue efforts.

“We do not yet know the scope of the damage, but this could be one of the deadliest and most devastating earthquakes since the 1934 tremor which devastated Nepal and Bihar,” said Jagan Chapagain, Asia/Pacific director of the International Federation of the Red Cross and Red Crescent Societies (IFRC).

The IFCR said it was extremely concerned about the fate of rural villages close to the epicentre of the quake, some 80 kilometres (50 miles) from the capital Kathmandu.

“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 Chapagain in a statement.

Historic tower collapses

The worst damage was reported in Kathmandu, where the historic nine-storey Dharahara tower, a major tourist attraction, was among the buildings to have been brought down.

At least a dozen bodies were taken away from the ruins of the 19th century tower, according to an AFP photographer who saw similar scenes of multiple casualties in other parts of the city.

While contact with Nepal was sporadic, a senior Nepalese diplomat warned that the final toll could run into many hundreds.

“We have received reports that there is a big loss of property and life in Nepal,” Krishna Prasad Dhakal, the deputy chief of mission at Nepal's Embassy in New Delhi, told AFP.

“Possibly hundreds of people have died in various parts of the country, particularly in Kathmandu and Pokhara."

At least 26 people were known to have died in India, including 17 in the eastern state of Bihar, while buildings in the capital New Delhi had to be evacuated.

The United States Geological Survey and India's meteorological service said the shallow quake struck 77 kilometres (48 miles) northwest of Kathmandu at 0611 GMT, with walls crumbling and families racing outside their homes.

“The walls of houses have collapsed around me onto the road. All the families are outside in their yards huddled together,” an AFP reporter said in Kathmandu.

Another resident recounted scenes of panic and mayhem.

“Everything started shaking. Everything fell down. The walls around the main road have collapsed. The national stadium's gates have collapsed,” Anupa Shrestha said.

The quake tore through the middle of highways in the capital and also caused damage to the country's only international airport which was briefly closed.

Kari Cuelenaere, an official at the Dutch embassy, said the impact had swept the water out of a swimming pool at a Kathmandu hotel where Dutch national day was being celebrated.

“It was horrible, all of a sudden all the water came up out of the pool and drenched everyone, the children started screaming,” Cuelenaere told AFP. “Some parts of the city fell down, there was dust rising... There were many (rescue) helicopters.

Aftershock tremors could be felt more than two hours after the initial quake.

Initially measured at 7.5 magnitude, the quake was later adjusted to 7.8, with a depth of 15 kilometres, the USGS said. It hit 73 kilometres east of the tourist town of Pokhara.

US sending disaster response team

The United States is sending a disaster response team to earthquake-hit Nepal and has authorised an initial $1 million to address immediate needs, the US Agency for International Development said Saturday.

The agency “is launching a DART team to respond to the #NepalQuake and has authorised an initial $1m to address immediate needs,” the Office of Foreign Disaster Assistance chief Jeremy Konyndyk said on Twitter.

Tremors felt across region

Witnesses and media reports said the tremors lasted between 30 seconds and two minutes.

“We are in the process of finding more information and are working to reach out to those affected, both at home and in Nepal,” Indian Prime Minister Narendra Modi said in a tweet.

The AFP office in Delhi was evacuated twice following the quake.

China's official Xinhua news agency said that two people, including an 83-year-old woman, were killed in the Tibet region as a result of the quake.

The earthquake was also felt across large areas of Bangladesh, triggering panic in the capital Dhaka as people rushed out onto the streets.

In the garment manufacturing hub of Savar, on the outskirts of Dhaka, at least 50 workers were injured after the quake set off a stampede in a garment factory, according to the private Jamuna television.

The area has a history of earthquakes, with a 6.8 magnitude quake that hit eastern Nepal in August 1988 killing 721 people.

A magnitude 8.1 quake killed 10,700 people in Nepal and eastern India in 1934.

Pakistan offers assistance to Nepal and India

Prime Minister Nawaz Sharif, who is in London on an official visit, has expressed his "deep shock on the reports of a massive earthquake that has caused devastation in Nepal and Northern India this morning", said a statement issued by the foreign office.

The statement also said, "the Government of Pakistan and its people extend their heartfelt condolences and sympathies to the governments and the peoples of Nepal and India on the tragedy that has caused loss of precious lives and properties".

According to the statement, the government of Pakistan has instructed its missions in the two countries to approach their respective host governments to ascertain the damages caused and the requirement of relief assistance.

The National Disaster Management Authority (NDMA) of Pakistan has been readied to take the relief assistance at a short notice, the statement said.

— With additional reporting from Irfan Haider in Islamabad.