Within sight of blackened and bloated corpses left unburied four days after a giant tidal wave devastated this and many other tiny islands, and amid the stench of thousands of drowned cattle, stunned and grieving rice farmers began rebuilding their homes today as if the 32nd cyclone to batter this vulnerable coast in 25 years was certain to be the last.

These farmers were among those who survived the killer cyclone and tidal wave that sent huge walls of water crashing over the islands off this impoverished country's southeastern coast Saturday.

President Hussein Mohammed Ershad, speaking to reporters during a helicopter tour to one of the other stricken islands, said, "I should say that the total number of deaths should not be less than 5,000 and a rough estimate is 5,000-10,000."

He called it "the worst tragedy in Bangladesh history" and estimated that about $50 million in emergency relief aid will be needed.

"Where else can we go? We have to stay here and live the best we can. We have nothing," said Rafiq ul-Islam, who lost both his parents when a 12-foot wave swept over this 20-square-mile island in the estuary of the Ganges River and virtually obliterated all signs of habitation.

Like most of the farmers and fishermen here, Islam and his family squatted on the mostly barren island six years ago when the riverbanks of nearby Sandwip Island washed away and put his thatched house under water.

Urirchar, newly formed from heavy silting from continuous erosion in southern Bangladesh's vast delta region, was vacant, Islam said, and "we thought we could start a new life here."

It was a hard-scrabble life, he admitted, but despite frequent, severe storms, most of the settlers managed to eke out a living by growing rice and grazing sheep and cows on the flat, open land.

That was until about midnight Friday when, after a day of steadily increasing wind and rain, the nightmare of the tidal wave -- technically referred to as a tidal bore by meteorologists -- began for the residents of Urirchar.

Ehidur Rahman, 60, recalled that he awoke in the early morning darkness to have a meal before beginning his fasting for the day in observance of the Moslem holy month of Ramadan and "saw little waves coming with heavy wind.

"All of a sudden, the wind grew and there was a wall of water. It swept us away from our house and we thought we were going into the river. We were clinging to the roof, all of us hanging onto the roof, but the big wind came and blew us apart from each other. Suddenly I found I was in the forest."

Nobody knows how many people live on this island, although local residents estimate about 10,000. But reporters on a helicopter tour over Urirchar island today saw that at most only hundreds of residents remained. All of the homes had been swept away, leaving hundreds of water-filled depressions. Bodies could be seen sprawled along the shoreline.

On the ground at Char Pir Baux, one of the main settlements on this island, survivors talked of the nightmare of the tidal wave. Some said that as the water struck, they raced to the only raised, concrete structures on the island -- two Forestry Department facilities built on pillars. Both were jammed with people, the survivors said, and when water began rising above the floor level, there was a grim scramble into the rafters for safety.

Some residents claimed there was no warning, but others said they had heard the series of three warnings from government radio broadcasts. But because so many storms lash this area, the survivors said no one paid much attention to the three warnings and that the crucial fourth one, if it was sounded, was not heard.

Survivors said there was no shade or shelter and they had no clothes to wear. And when President Ershad, on his tour of the stricken island of Manpura, handed out emergency relief money, those here said there would be no use for the money because there is no place to spend it and nothing left to buy.

Ershad was asked why, after so many cyclones, he did not order these islands to be evacuated.

"It is not possible to clear the islands because of the population pressures on the land," he said of this densely populated country. "During the winter, this is a fine place to live," he said. "And where will the people go? We have to have people on these islands. Most of the time, they just depend on God. They just try their luck."

In the capital at Dhaka, a briefing officer estimated that almost 17,000 structures had been destroyed, with 122,000 damaged. An estimated 140,000 head of cattle were said to be lost and 472,000 acres of cropland damaged. Ershad said that only $2 million in emergency aid had been pledged.

In Washington, U.S. aid administrator M. Peter McPherson announced that the United States would provide $300,000 in emergency cash assistance and would give another $250,000 to the Red Cross.