BANDA ACEH, Indonesia (CNN) -- The number of dead in Indonesia has risen five-fold to 27,174, almost doubling the death toll from the massive underwater earthquake and the equally massive tsunami that followed it.

Overturned vehicles and debris are spread throughout a bus stand in Galle, Sri Lanka, Tuesday.

he latest numbers, confirmed by the Ministry of Health in Jakarta on Wednesday, push the final toll from Sunday"s catastrophe to over 56,000.

Officials could not reach some remote areas, like Indonesia"s Aceh province, India"s Andaman and Nicobar Islands and the Maldives, until Tuesday, and once there, they found scenes much worse than they imagined.

The "putrid stench of the dead" hung heavily Tuesday over Banda Aceh as officials slowly came to grips with the devastation.

The 9.0 magnitude earthquake struck off the western-most portion of Indonesia"s northern Sumatra Island early on Sunday.

"The center of Banda Aceh has been absolutely devastated," said CNN"s Mike Chinoy from the capital of Aceh province. "There are still bodies lying in the street."

As far away as Somalia on Africa"s east coast, reports trickled in of fishermen swept out to sea and swimmers lost.

Jan Egeland of the United Nations said entire villages were swept away in Somalia, and Kenya television reporter Lillian Odera said "hundreds were killed" there.

In all, at least 12 countries -- including the Maldives, Myanmar, Malaysia, Bangladesh and Tanzania -- were affected by the monstrous waves.

Along with many private humanitarian aid groups, the United States, Australia, Germany, Japan and other nations have pledged relief to help victims throughout the region.

More than 18,000 of those confirmed dead were in Sri Lanka, where the giant waves swept a 1,000-passenger train off its tracks, and the dead and injured overwhelmed hospitals and medical workers.

"It"s a huge situation, and there are instances where bodies are decomposing, and they"re being photographed and fingerprinted" before being taken to mass graves, said Harim Peiris, spokesman for President Chandrika Bandaranaike Kumaratunga.

"And there are instances where entire families have been wiped out."

Kumaratunga announced that Friday would be a national day of mourning.

Twelve trucks carrying rice, lentils and sugar left a U.N. World Food Program depot in the Sri Lankan capital of Colombo on Tuesday, headed to the country"s southern and eastern coasts, The Associated Press reported.

The U.N. mission was also dispatching water bottles, bed sheets and cooking utensils, AP said. (Disease threat)

Peiris said the most essential need at the moment was to keep people alive with cooked meals and clean drinking water -- and only later to begin rebuilding.

As aid began to arrive in several countries, families continued to flock to makeshift morgues seeking lost loved ones as more than a million people have been left homeless in Indonesia, India, Sri Lanka and Thailand.

Authorities across the region are running out of places to put the dead -- lining them up in schools and stacking them in the street -- as food aid and other supplies for survivors are making their way to affected areas.

The United Nations is asking donor countries to dig deeper, saying this will likely be the costliest natural disaster ever.

"People need help fast," said one man in Colombo, Sri Lanka, where flags were at half-staff.

"There"s no power, there"s no petrol, there"s no movement, there"s no support getting through to the injured, and I believe there are bodies that need to be identified and transported out of there. With this heat, sanitation problems will arise."

The United States has pledged to add an additional $20 million in aid for the disaster, to $15 million previously promised, the State Department announced Tuesday. (List of aid agencies)

At the Pentagon, officials said plans are being worked out to dispatch Navy ships, supplies, helicopters, and hundreds of troops for humanitarian relief in Thailand.

The magnitude-9.0 quake struck about 7 a.m. Sunday (0000 GMT) and was centered about 160 kilometers (100 kilometers) off the coast of Indonesia"s Sumatra island at a depth of about 10 kilometers (6.2 miles).

The tsunamis" paths left massive, indiscriminate destruction in areas that included some of the world"s richest tourist sites and impoverished villages. (Shock and loss)

Most of the fatalities in Sri Lanka were in the eastern district of Batticaloa, authorities said.

The Sri Lankan government declared a state of emergency, and, along with the government of the Maldives, requested international assistance, the U.N. Office for the Coordination of Humanitarian Affairs reported.

India also was reeling. Press Trust of India, the government news agency, said at least 9,500 Indians were killed and more bodies were being recovered.

Along India"s southeastern coast, thousands of fishermen who were at sea when the waves thundered ashore have not returned.

Along the coast, brick foundations were all that remained of village homes.

In Tamil Nadu state, sources said 6,000 people were confirmed dead, and estimates put the death toll at 3,000 on the remote Andaman and Nicobar islands, where dozens of aftershocks were centered. (Full story)

Asian government officials conceded Monday that they failed to issue public warnings that could have saved many lives. (Full story)

In Thailand, authorities said at least 1,010 people were dead and hundreds missing along the country"s west coast -- home to 40 percent of Thailand"s $10 billion tourist industry. ( Death toll could reach 2,000)

Khun Poom Jensen, the 21-year-old autistic grandson of King Bhumibol Adulyadej, was among those killed.

One of the heaviest hit areas was Phuket, where 130 people were dead and as many as 600 people were believed to have been washed out to sea.

Many of the dead and missing are believed to be foreign nationals who were on the beach when the massive waves hit.

A total of 55 of non-nationals in the region have been reported killed, including 12 Americans, according to government figures.

One of the survivors was a 20-month-old Swedish boy who turned up in the Phuket International Hospital.

It was only after the news media published his photo that relatives in Europe contacted the hospital to identify him. (Full story)

CNN"s Mike Chinoy in Indonesia, Aneesh Raman in Thailand; Satinder Bindra in Sri Lanka; Atika Shubert in Indonesia; and Suhasini Haidar in India, contributed to this report.