Rescuers were struggling to reach the mountains of northeast Pakistan where thousands of cold and wet earthquake survivors spent a second night in the open, as the death toll rose to nearly 20,000.
The roads leading into Pakistani-controlled Kashmir -- the area worst affected by Saturday's 7.6 magnitude quake -- were blocked by landslides. Power and water supplies have been cut off, and hospitals destroyed.
In many places people dug through the night Monday with their bare hands in an often futile attempt to reach friends and relatives trapped in the rubble, and anger started to build as help failed to arrive.
"Our town has been turned into a heap of rubble and so many people have died but there is absolutely no help in the past two days," said Mohammad Zaheer, a survivor in the shattered town of Balakot.
"We survived the earthquake but now we realise we will die of hunger and cold."
The United Nations said more helicopters were needed urgently to bring rescue equipment and aid to stricken villages high in the Himalayas.
"We are seeing enormous suffering and facing enormous challenges," Jan Egeland, UN coordinator of humanitarian affairs and emergency relief, told AFP. "We're talking about millions affected by this."
He said Pakistan had deployed its own substantial fleet of helicopters to search for survivors but the scale of the disaster required more choppers and small fixed-wing aircraft.
The United States responded by offering eight military helicopters -- five twin-rotor Chinooks and three Blackhawks based in neighbouring Afghanistan -- and two C-130 aircraft loaded with tents, blankets and other relief supplies.
Afghanistan also said it would send four military helicopters, medical teams and three tonnes of medicine.
As international rescue teams with sniffer dogs and specialist equipment began arriving in Pakistan, the authorities said over 19,100 had been confirmed dead and over 42,000 people were injured.
But Pakistani military spokesman Major General Shaukat Sultan said the death toll would continue to soar, and an official in Pakistani-held Kashmir said the eventual toll in that region alone would top 30,000.
Pakistani officials said more than 11,000 people had been confirmed dead in the town of Muzaffarabad, the capital of Pakistan-controlled Kashmir.
"Muzaffarabad is devastated," said the local minister for works and communication, Tariq Farooq.
The earthquake struck Saturday morning as schools were beginning classes, and hundreds if not thousands of children are feared to have died when buildings collapsed or were engulfed by landslides.
Officials said the hospitals in Muzaffarabad had been hard hit, and the Pakistani military flew in special teams of surgeons and set up field hospitals in the town.
"There's a huge need for field hospitals, water, sanitation and for food," Gerhard Putman-Cramer, head of the UN's Disaster Assessment and Coordination (UNDAC) team, told AFP.
The earthquake also hit the Indian-held zone of Kashmir hard with officials there saying over 600 people were confirmed dead. They also warned many remote villages had yet to be reached and the death toll would likely rise.
The epicentre was close to the dividing line between the Indian- and Pakistani-controlled zones of Kashmir, and scores of soldiers on both sides died when their heavily-fortified positions collapsed around them.
Nuclear-armed India and Pakistan have fought two wars over Kashmir, but a peace process is under way and Indian Prime Minister Manmohan Singh has reached out to Pakistan President Pervez Musharraf to offer help.
Offers of aid and assistance have begun pouring in from around the world.
The United States it had provided 50 million dollars in initial aid. The World Bank offered 20 million dollars while the Asian Development Bank pledged 10 million dollars.
Japan said it had sent a 50-strong emergency relief team and Britain, which has a large South Asian community, said it was sending an initial 100,000 pounds (176,000 dollars) and a 60-strong rescue and relief team.
