A powerful earthquake struck Nepal Saturday, killing hundreds of people across a swath of four countries as the violently shaking earth collapsed houses, leveled centuries-old temples and triggered avalanches on Mt. Everest. It was the worst temblor to hit the poor South Asian nation in over 80 years.

At least 1,910 people were confirmed dead in Nepal, according to authorities. Another 34 were killed in India, 10 in Tibet and two in Bangladesh. Two Chinese citizens died at the Nepal-China border. Authorities warned the death told was set to rise as reports came in from areas far away..

Pushpa Das, a laborer, ran from the house when the first quake struck but could not escape a collapsing wall that injured his arm.

"It was very scary. The earth was moving ... I am waiting for treatment but the (hospital) staff is overwhelmed," he said, gingerly holding his right arm with his left hand. As he spoke dozens of more people showed up with injuries, mostly from falling bricks.

The quake with a preliminary magnitude of 7.8 struck before noon and was most severely felt in the capital as well as the densely populated Kathmandu Valley. A magnitude-6.6 aftershock hit about an hour later, and smaller aftershocks continued to ripple through the region for hours.

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PHOTOS: Hundreds dead in powerful Nepal quake

Within hours of the quake, hospitals had filled up with hundreds of injured people. With organized relief and rescue largely absent, many were brought to hospitals by friends and relatives in motorized rickshaws, flatbed trucks and cars. Residents used their bare hands, crowbars and other tools to dig through rubble and rescue survivors.

The earthquake also shook several cities across northern India, and was felt as far away as Lahore in Pakistan, Lhasa in Tibet, and in Dhaka, Bangladesh. Following the quake, Kathmandu's international airport was shut down.

While the extent of the damage and the scale of the disaster are yet to be ascertained, the quake will likely put a huge strain on the resources of this poor country best known for Everest, the highest mountain in the world. The economy of Nepal, a nation of 27.8 million people, is heavily dependent on tourism, principally trekking and Himalayan mountain climbing.

A senior mountaineering guide, Ang Tshering, said an avalanche swept the face of Mt. Everest after the earthquake, and government officials said at least 8 climbers were killed and 30 injured. Their nationalities were not immediately known.

Tshering of the Nepal Mountaineering Association said the avalanche occurred between the Khumbu Icefall, a rugged area of collapsed ice and snow, and the base camp where most climbing expeditions have their main camps.

The quake's epicenter was 80 kilometers (50 miles) northwest of Kathmandu, and it had a depth of only 11 kilometers (7 miles), which is considered shallow in geological terms. The shallower the quake the more destructive power it carries, and witnesses said the trembling and swaying of the earth went on for several minutes.

As the quake began to intensify, residents ran out of homes and buildings in panic. Clouds of dust began to swirl around them. Large cracks opened up on streets and walls.

Several buildings collapsed in the center of the capital, the ancient Old Kathmandu, including centuries-old temples and towers, said resident Prachanda Sual.

Among them was the nine-story Dharahara Tower, one of Kathmandu's landmarks built by Nepal's royal rulers as a watchtower in the 1800s and a UNESCO-recognized historical monument. It was reduced to rubble and there were reports of people trapped underneath.

Hundreds of people buy tickets on weekends to go up to the viewing platform on the eighth story.

Video footage showed people digging through the rubble of the bricks form the collapsed tower, looking for survivors.

The Kathmandu Valley is densely populated with nearly 2.5 million people, and the quality of buildings is often poor.

In Kathmandu, dozens of people were gathered in the parking lot of Norvic International Hospital, where thin mattresses were spread on the ground for patients rushed outside, some wearing hospital pajamas. A woman with a bandage on her head sat in a set of chairs pulled from the hospital waiting room.

Doctors and nurses hooked up some patients to IV drops in the parking lot, or were giving people oxygen.

The U.S. Geological Survey revised the magnitude from 7.5 to 7.9 but then lowered it to 7.8. It said the quake hit at 11:56 a.m. local time at Lamjung. It was the largest shallow quake since the 8.2 temblor off the coast of Chile on April 1, 2014.

The quake -- with the same magnitude as the one that hit San Francisco in 1906 -- was about 16 times more powerful than the 7.0 quake that devastated Haiti in 2010.

A magnitude 7 quake is capable of widespread and heavy damage while an 8 magnitude quake can cause tremendous damage.

A Swedish woman, Jenny Adhikari, who lives in Nepal, told the Swedish newspaper Aftonbladet that she was riding a bus in the town of Melamchi when the earth began to move.

"A huge stone crashed only about 20 meters (yards) from the bus," she was quoted as saying. "All the houses around me have tumbled down. I think there are lot of people who have died," she told the newspaper by telephone. Melamchi is about 45 kilometers (30 miles) northeast of Kathmandu.

Residents reported seeing trails of destruction -collapsed walls, broken windows and fallen telephone poles - as they drove through the capital, along with streets filled with terrified people.

But scattered reports also indicated that most buildings in the capital did not collapse.

"It's too early to make any assessment but the damage isn't as bad as it could have been," said Liz Satow, the Nepal director for the air group World Vision. She said she drove from Kathmandu to the nearby town of Lalitpur and said that while there was considerable damage, most buildings were still intact.

Nepal suffered its worst recorded earthquake in 1934, which measured 8.0 and all but destroyed the cities of Kathmandu, Bhaktapur and Patan.

The sustained quake also was felt in India's capital of New Delhi and several other cities.

India's Prime Minister Narendra Modi called a meeting of top government officials to review the damage and disaster preparedness in parts of India that felt strong tremors. The Indian states of Uttar Pradesh, Bihar and Sikkim, which share a border with Nepal, have reported building damage. There have also been reports of damage in the northeastern state of Assam.

Pakistan Prime Minister Nawaz Sharif offered "all possible help" that Nepal may need.

The Associated Press contributed to this report