In the shattered streets of Muzaffarabad, the capital of Pakistani Kashmir, an Associated Press reporter saw shopkeepers scuffle with a group of people trying to break into shuttered businesses on Monday.
They beat each other with sticks and threw stones and some people suffered head wounds.
No police were in the area. Residents said desperate survivors also targeted deserted homes, and even gas stations.
Survivors lacked food and water amid little sign of any official coordination of relief in the devastated city of 600,000 - where at least 11,000 people have died.
About 2000 people huddled around camp fires through the cold night on a football field on the city's university campus, where most buildings had collapsed and hundreds were feared buried in classrooms and dormitories. Soldiers burrowed into the concrete with shovels and iron bars.
"I don't think anybody is alive in this pile of rubble," rescue worker Uzair Khan said. "But we have not lost hope."
Toll estimates ranged from 20,000 to more than 30,000 on Monday.
The massive earthquake
left gaping cracks in roads
The United Nations said more than 2.5 million people were left homeless by Saturday's 7.6-magnitude quake, and doctors have warned of an outbreak of disease unless more relief arrives soon.
With landslides blocking roads to many of the worst-hit areas, Pakistan's army was flying food, water and medicine into the disaster zone.
International relief efforts cranked into action, with flights carrying rescue teams and supplies arriving in Pakistan.
Eight US military helicopters from Afghanistan arrived in Islamabad with provisions. Washington pledged up to $50 million in relief and reconstruction aid, US Ambassador Ryan Crocker said.
"The magnitude of this disaster is utterly overwhelming," Crocker said. "We have under way the beginning of a very major relief effort."
Most of the dead were in Pakistan's mountainous north. India reported more than 800 deaths, and Afghanistan reported four.
No food for three days
On a playing field, Mohammed Ullah Khan, 50, said a few biscuits handed out by relief workers were his only food for three days.
"My children are now on a hillside, under the open sky, with nothing to eat"
Mohammed Ullah Khan,
His wife, who suffered a fractured leg, was wrapped in a yellow quilt beside him. Their three-storey home had collapsed in the quake.
His family of 10 people survived because they were on the top floor, which crashed to the ground.
"My children are now on a hillside, under the open sky, with nothing to eat," he said.
A doctor, Iqbal Khan, said there was a serious risk of outbreaks of diseases such as diarrhoea and pneumonia if drinking water and other relief supplies did not arrive quickly.
"These people feel as if there is no one to take care of them," he said.
Drinking stream water
The city had no electricity, and people collected water from a mountain stream.
Pakistani President General Pervez Musharraf said the earthquake was the country's worst on record and appealed for urgent help, particularly cargo helicopters to reach remote areas.
International rescuers and aid
arrived in Pakistan
US President George Bush on Sunday promised cash and said he had told Musharraf: "We want to help in any way we can."
India, a long-time rival of Pakistan, offered help in a gesture of cooperation. The nuclear-armed neighbours have been pursuing peace after fighting three wars since independence from British rule in 1947, two of them over the Kashmir region.
Pakistani Prime Minister Shaukat Aziz said his country's toll was 19,396 and was expected to rise.
Rising death toll
Senior officials in Pakistani Kashmir put the toll much higher. The top elected official in the region, Sardar Sikandar Hayat, said that more than 25,000 people had died there, with countless injured.
Tariq Mahmood, the province's communications minister, put the toll at more than 30,000. Troops "have not started relief work in remote villages where people are still buried in the rubble, and in some areas nobody is present to organise funerals for the dead", Mahmood said.
The quake was felt across a wide swathe of South Asia, with damage spanning at least 400km from Jalalabad in Afghanistan to Srinagar in Indian-administered Kashmir.
In Geneva, the United Nations urgently appealed for donations, including for at least 200,000 winterised tents.
Two American planes
By Monday, at least two American aeroplanes with relief supplies had arrived at Islamabad. Planes with international aid arrived from Turkey, Britain, Japan and the United Arab Emirates. Russia, China and Germany also offered assistance.
"Pakistan is one of our closest allies in the war on terror and we want to help them in this time of crisis"
Sergeant Marina Evans,
US military spokeswoman, Kabul
US forces in Afghanistan sent five Chinook transport helicopters and three Black Hawk helicopters to Pakistan.
"Pakistan is one of our closest allies in the war on terror and we want to help them in this time of crisis," said Sergeant Marina Evans, a US military spokeswoman in Kabul. "The terrorists make us out as the infidels, but this is not true and we hope this mission will show that."
On the Indian side of the militarised Kashmir border - where at least 650 have died - hundreds of Kashmiris spent Sunday night outside in the cold after rumours of another aftershock.
"I don't want to take a chance. What if there is a quake?" said Atiqa Bano, a 65-year-old housewife.