Tsunami survivors face aftershocks and disease as toll of the dead rises

The death toll from the tsunami which devastated coastal areas of south Asia approached 25,000 last night as the United Nations warned that it could be the worst natural disaster of modern times.

More than two million people have lost their homes and tens of thousands were injured, with many more still unaccounted for, after the huge wave triggered by a massive under-sea earthquake off Sumatra in Indonesia.

With bodies left to rot in the tropical sun, aid agencies warned of cholera and dysentery epidemics as local officials struggled to cope with the scale of the disaster.

There were a further 14 aftershocks yesterday as fears mounted for the inhabitants of the remote Andaman and Nicobar islands where contact has been lost and tens of thousands are now feared dead. A £2bn military base on the archipelago, thought to garrison up to 8,000 soldiers, was swept away when the waves struck, a senior Indian official told The Independent.

Hundreds of people also died and entire villages and towns disappeared in Somalia on the east coast of Africa - the furthest point from the epicentre to be affected.

Tens of thousands of tourists were trying to get out of the region as it emerged that dozens of holidaymakers, including 15 Britons, had lost their lives in the Boxing Day disaster. Ten have died in Thailand, three in Sri Lanka and two in the Maldives. Plans to celebrate New Year at Asian beach resorts were being cancelled across the region. Governments were accused of doing too little to warn their populations and there were calls for an international seismic monitoring system to prevent a repeat of the tragedy.

The UN Emergency Relief Co-ordinator Jan Egeland said the effects of the disaster would be particularly dramatic because so many of the places hit had big, poor populations, crammed into sub-standard housing. "This may be the worst natural disaster in recent history because it is affecting so many heavily populated coastal areas ... so many vulnerable communities. The first wave has already brought tens of thousands of casualties," Mr Egeland said.

The second wave of devastation, he warned, would be the millions of people affected by the quake and tsunami, many of them living in poor coastal and fishing communities, who have had their livelihoods washed away. The International Federation of the Red Cross and Red Crescent Societies in Geneva said it would need $6.5m (£3.3m) to begin emergency assistance. The United States dispatched disaster teams and prepared a $15m aid package to the Asian countries.

An estimated 10,200 people were killed in Sri Lanka - some 2,000 bodies were recovered in Tamil rebel-controlled territory. More than 1.5 million Sri Lankans were displaced from their homes.

In the village of Karapitiya relatives scrambled over piles of corpses, holding shirts or handkerchiefs to their noses to ward off the stench. In Banda Aceh, on the north-western tip of Sumatra and the closest land point to the epicentre of the quake, the death toll was expected to rise to as much as 10,000 - three times the initial estimate. Some 1,500 people were buried in one mass grave yesterday afternoon. The stench of rotting flesh pervaded the city. "It smells so bad ... the human bodies are mixed in with dead animals like dogs, fish, cats and goats," said Buyung Lelana, a marine colonel, who was leading the evacuation effort which was being hampered by power cuts and failed telephone networks. On the outskirts of the city, relatives searched among 500 corpses lined up under plastic tents. Volunteers laid the bodies of children in rows in their sarongs. Others were stacked in white fish crates.

Even when the dead have been found, burying them according to Islamic tradition is proving difficult. One man, Rajali, said he had lost his wife and two children but couldn't find dry ground to bury them.

To hamper rescue efforts still further, it emerged that a police barracks in Banda Aceh had collapsed killing at least 200 police officers and their families. At the Cut Meutia hospital, doctors said they were running out of medicine while in the Bierun area, the local mayor warned of a shortage of coffins.

The Indonesian military deployed 15,000 troops to search for survivors and three days of national mourning was declared by President Susilo Bambang Yudhoyono.

The scale of the disaster in India was also worse than first feared. The state hit hardest was Tamil Nadu where more than 3,000 people were confirmed killed - nearly half the Indian death toll. In neighbouring Andhra Pradesh some 1,300 people were still missing presumed dead. Among them were 200 Hindu pilgrims lost as they took part in a holy bathing ritual on the beach.

It was estimated that three-quarters of the dead were the wives and children of local fisherman who were too weak to swim to safety, officials said yesterday. The Indian coastguard continued to discover the wrecks of fishing trawlers and small boats.

Survivors in the Andaman Islands, 900 miles east of the mainland, where there is little high ground to offer sanctuary, gathered up what possessions they could and trekked miles through jungle to government shelters. In the neighbouring Nicobar Islands reports suggested thousands more may have died on the outlying Car Nicobar Island which has a population of 18,000.

The Thai government said more than 900 people have been killed in the disaster there, nearly 40 of them foreigners. Among the dead in the region as a whole were eight Americans, 11 Italians, 10 Norwegians and nine Japanese. Irish, Australian, New Zealand, German, South African, Swedish, Russian, Malaysian, South Korean and Mexican tourists also died.

Also killed was Poom Jensen, the Thai American grandson of King Bhumipol Adulyadej, who died while jet-skiing at Krabi.

Phuket's Patong beach took the bulk of the damage and two-thirds of Thailand's fatalities occurred there. One of them was a six-month-old Australian baby, swept from her father's arms as he stumbled to safety. The child's uncle said: "He thought he had the baby in his hands, but all he had was clothes."

Burma's military government confirmed that 34 people had been killed by the tsunami. It emerged that 52 people had drowned in the Maldives with six of the 200 islands in the archipelago evacuated. In Britain, there was desperate demand for information about the victims. The BBC was inundated with complaints that the emergency hotline set up by the Foreign Office was constantly engaged. Some families resorted to e-mailing the BBC as a way of voicing their anger.

Meanwhile, John Prescott took charge of the UK action to help with the earthquake disaster relief while Tony Blair began a Middle East sunshine holiday. No 10 is braced for criticism that continuing his holiday would be insensitive given the scale of the disaster.