About 40,000 people were injured in the 7.6 magnitude quake that struck parts of South Asia on Saturday, Pakistan military spokesman Major-General Shaukat Sultan said.
"More than 18,000 are dead and 41,000 injured. Most of the casualties have occurred in Kashmir followed by North West Frontier Province," Sultan said on Sunday, warning the toll could go far higher.
"There are many areas that so far have not been reached.The death toll of 18,000 could be manifold more as we reach more areas and as we discover more and more dead bodies buried under the rubble," he told CNN.
"There are many villages and even small towns that have been wiped off the face of the earth," he added.
Most of the casualties occurred
"This disaster is by far the biggest in its magnitude and scale so far that we have witnessed in Pakistan's history."
Indian military officials in the Indian-administered zone of Kashmir have so far confirmed that at least 300 people are dead in the region from the quake.
There were also scattered reports of casualties in towns and
villages across northern Pakistan, India and southern Afghanistan.
Rescuers grappled with rain that turned dirt and debris into sticky muck, while aftershocks rattled an area stretching from Afghanistan across northern Pakistan into India's portion of the disputed Himalayan region of Kashmir.
The massive earthquake triggered landslides, toppled an apartment building and flattened villages of mud-brick homes near the border between Pakistan and India, leaving behind a wide swath of devastation.
The United Nations sent emergency coordinators to worst-hit Pakistan on Sunday. The world body also said it was working with Afghanistan and India.
Pakistan's dead included 250 girls crushed by rubble when their school collapsed, and 200 soldiers on duty in Kashmir.
For hours on Saturday, aftershocks from the 7.6-magnitude quake rippled across the region as rescue teams struggled through debris in a search for survivors.
Relatives sit with injured victims
outside a hospital in Abbottabad
Hospitals evacuated quake victims, some hooked up to intravenous drips, onto their lawns, fearing tremors could cause more damage. As night fell, rain and hail disrupted the recovery effort.
In Pakistan, in the northern town of Mansehra, a shop owner named Haji Fazal Ilahi stood vigil over the body of his 14-year-old daughter, which lay under a sheet on a hospital mattress. He said his wife, a daughter and a brother also perished under the debris of their home.
"I could see rocks and homes tumbling down the mountains," said Fazal Ilahi, who was driving to his village of Garlat when the quake struck. "When I reached my village, there was nothing left of my home."
Aid from India
In a show of solidarity, India offered assistance and condolences to its longtime rival, Pakistan. The neighbours, which are engaged in a peace process, have fought three wars since independence from British rule in 1947, two of them over the divided region of Kashmir that was devastated in the quake.
"While parts of India have also suffered from this unexpected natural disaster, we are prepared to extend any assistance with rescue and relief which you may deem appropriate," Indian Prime Minister Manmohan Singh said in a message to Pakistan President Pervez Musharraf.
Sardar Mohammed Anwar, the top government official in Pakistani Kashmir, said about 1000 civilians died in the region.
"This is my conservative guess, and the death toll could be much higher," Anwar told Pakistan's Aaj television station. He said most homes in Muzaffarabad, the area's capital, were damaged, and schools and hospitals had collapsed.
Rescuers remove debris from the
collapsed Margalla Tower building
At least 1600 people died in Pakistan's North West Frontier Province, said Akram Durani, the province's top elected official. Ataullah Khan Wazir, police chief in the northwestern district of Mansehra, said the authorities there had pulled the bodies of 250 students from a girls' school that collapsed.
"This tragic incident happened in Ghari Habibibullah," a district village, he said. About 500 students were injured.
Dozens of children were feared killed in other schools.
In the capitals of Pakistan, India and Afghanistan, buildings shook and walls swayed for about a minute, and panicked people ran from their homes and offices.
Communications throughout the region was cut.
"It is a national tragedy," said Pakistan spokesman Sultan. "This is the worst earthquake in recent times."
Pakistani Kashmir centre
Homes in Sopore, about 60km
from Srinagar, were damaged
The US Geological Survey said on its website that the quake hit at 8.50am local time and had a magnitude of 7.6. It was centred about 100km northeast of Islamabad in the forested mountains of Pakistani Kashmir.
Damage was extensive in Kashmir, the disputed Himalayan territory divided between India and Pakistan.
At least 800 people were injured and about 2700 homes were destroyed or damaged across Jammu-Kashmir, said senior state official B B Vyas.
Army soldiers and local volunteers rescued people from under the debris of collapsed houses. Telephone lines were down and bridges had developed cracks, but traffic was passing over them.
Musharraf and Prime Minister Shaukat Aziz ordered the Pakistani military to extend "all-out help" to quake-hit areas and appealed to the nation to stay calm.
Helicopters and C-130 transport planes took troops and supplies to damaged areas, but landslides were hindering rescue efforts.
Apartment building collapse
The quake brought down a 10-storey apartment building in Islamabad, and at least 10 people died. The dead included an Egyptian diplomat, hospital doctors said. The Japanese Foreign Ministry in Tokyo said two Japanese died. At least 126 survivors were being treated in hospitals.
Rescue workers stand on the
debris of a building in Lahore
A man named Rehmatullah who lived nearby said he saw dust from the buckled building from his bathroom window.
"I rushed down, and for some time you could not see anything because of the dust. Then we began to look for people in the rubble," he said. "We pulled out one man by cutting off his legs."
Aided by two large cranes, hundreds of police and soldiers helped remove chunks of concrete.
In Abbottabad, north of Islamabad, dozens of injured quake victims and other patients lay on the lawn of the city hospital, as staff with loudspeakers appealed to the public for food and other relief supplies.
The quake also jolted parts of Bangladesh, but no casualties or damage were reported there.