Government officials warned the toll from the deadliest tidal waves in 120 years could climb by tens of thousands.
Bodies,filled beaches and choked hospital morgues, raising fears of disease across an 11-nation arc of destruction.
In Indonesia, closest to Sunday's 9.0 magnitude quake that sent walls of water crashing into coastlines thousands of miles away, the official death toll stood at about 19,000. But the country's vice president said the number could reach 25,000.
CBS News Correspondent Susan Roberts reports that in Indonesia many streets are already filled with rotting corpses and rescue workers say that without clean water, an.
"Water and sanitation and emergency health," says John Budd of UNICEF, "that is the most important thing at the moment."
More than 18,700 people died in Sri Lanka, 4,000 in India and 1,500 in Thailand.
Desperate residents on Indonesia's Sumatra Island - 100 miles from the quake's epicenter - looted stores Tuesday. "There is no help, it is each person for themselves here," district official Tengku Zulkarnain told el-Shinta radio station.
The disaster could be the costliest in history, with "many billions of dollars" of damage, said U.N. Undersecretary Jan Egeland. Hundreds of thousands have lost everything, and millions are living with polluted drinking water and no health services, he said.
The U.S. has sent disaster teams to tsunami sites including Thailand and Indonesia and plans to offer $15 million in aid. Japan pledged $30 million. Australia pledged $8 million. When asked about the level of U.S. aid by CBS News Early Show co-anchor Harry Smith, Secretary of State Colin Powell said, "It's a start" and added, "I think a lot more aid is going to be needed."
In Galle, Sri Lanka, officials used a loudspeaker fitted atop a fire engine to tell residents to place bodies on the road for collection. Muslim families used cooking utensils and even their bare hands to dig graves. Hindus in India, abandoning their tradition of burning bodies, asked for help with mass burials.
Soldiers and volunteers in Indonesia combed through destroyed houses to try and find survivors - or bodies. In Thailand's once-thriving resorts, volunteers dragged scores of corpses - including at least 700 foreign tourists - from beaches and the remains of top-class hotels.
In an eerie echo of 9/11, posters are going up with photos of loved ones, reports CBS News Correspondent Barry Petersen from Thailand. The message is always the same: 'Call, please, if you've seen this person somewhere alive.' Peterson says the hardest thing about reporting the story is talking to those still clinging to hope for their loved ones. They say through their tears they still believe there can be a miracle. Sadly, it's pretty clear for those people miracles in the days ahead will be few, if any.
But, amid the devastation, stories of survival still emerged.
In Malaysia, a 20-day-old baby was found floating on a mattress soon after the waves hit Sunday. She and her family were reunited.
A blond-haired 2-year-old Swedish boy found sitting alone on a road in Thailand and taken to a hospital was reunited with his uncle, who saw the boy's picture on the hospital's Web site.
"When I saw Hannes on the Internet, I booked an air ticket to come here in less than five hours," said a man who identified himself only as Jim. Hannes Bergstroem's mother died in the tsunami; his father was in another hospital, the Swedish paper Aftonbladet reported.
The geographic scope of the disaster was unparalleled. Relief organizations used to dealing with a centralized crisis had to distribute resources over 11 countries in two continents.
In Sri Lanka, the Health Ministry dispatched 300 physicians to the disaster zone, dropping them off by helicopter.
Sri Lankan Foreign Minister Lakshman Kadirgamar said the United States was sending helicopters, and an airborne surgical hospital from Finland arrived in Sri Lanka. A German aircraft was en route with a water purification plant. "A great deal is coming in and they are having a few problems at the moment coordinating it."
UNICEF officials said that about 175 tons of rice arrived in Banda Aceh, Indonesia, late Monday and six tons of medical supplies were expected to arrive by Thursday. But most basic supplies were scarce.
Scores of people were killed in Malaysia, Myanmar, Bangladesh, and Maldives. Deaths were even reported in Africa - in Somalia, Tanzania and Seychelles, close to 3,000 miles away.
It was the deadliest known tsunami since the one caused by the 1883 volcanic eruption at Krakatoa - located off Sumatra's southern tip - which killed an estimated 36,000 people.
The streets in Banda Aceh were filled with overturned cars and rotting corpses. Shopping malls and office buildings lay in rubble, and thousands of homeless families huddled in mosques and schools.
Indonesia barred foreigners from its Aceh province until Monday because of a long-running separatist conflict. Communications lines were still down and remote villages had yet to be reached.
"I heard that many bodies are still in the hospitals and many places. They should be buried in mass graves but there is no one to dig graves," said Steve Aswin, an emergency officer with UNICEF in Jakarta.
Sri Lankan police waived the law calling for mandatory autopsies, allowing rotting corpses to be buried immediately.
On the remote Indian islands of Andaman and Nicobar, off the northern tip of Sumatra, officials still hadn't established communications. An estimated 3,000 deaths were not yet counted in the official toll.
Also on Tuesday, India's government said a nuclear power plant damaged by tidal waves was safe and that there was no threat of radiation.