The bodies of 25,000 victims have already been buried, some 19,500 by municipal workers in Bam itself and the rest by local people in surrounding areas, state radio said, quoting an official.

Attention turned to the grim task of recovering thousands of corpses from the rubble and burying the dead amid growing fears for the health of survivors, as Iran's top leadership visited Bam for the first time since Friday's quake.

A UN official warned that even a common cold or influenza could prove fatal as tens of thousands spent another night in freezing temperatures and minimal shelter.

"When we talk about a public health problem we are talking about the risk of a massive outbreak of all kinds of illnesses and diseases," Hamid Marashi, Iran communications officer for the United Nations Children's Fund (UNICEF), told AFP.

"These could be even just the common cold and the flu, which if untreated can spread very quickly and cause enormous problems for the survivors."

Residents were "very vulnerable because they are sleeping out in very cold temperatures", Marashi said. "Another risk is that of dysentery because of the poor sanitary environment that people are living in."

The body recovery operation only appeared to have covered a small proportion of the city, which was at the epicentre of the devastating quake that measured 6.7 on the Richter scale.

Mohammad Ehsani, a surgeon working in the Imam Khomeini hospital, said: "I think we can say that the search for survivors has ended. The main objective now is to take care of the wounded, get shelter, food and water to the survivors and to bury the dead as quickly and as urgently as possible.

"All they have been pulling out from the rubble for the last two days have been dead bodies."

President Mohammad Khatami and several government ministers flew to Bam to inspect damage and rescue work.

His visit followed one earlier in the day by the country's supreme leader Ayatollah Ali Khamenei who spent three hours in the town.

Khatami acknowledged on arrival: "The scale of the tragedy is very high.

"Whatever we do, it will still be too little," he said. "Hopefully, as time goes by more aid will arrive."

Wearing a clerical grey tunic, he first flew over the city aboard a helicopter to get an overview of the damage before touring the town.

Earlier, Khamenei, accompagnied by dozens of bodyguards, also toured the centre of town and its 2,000-year-old citadel which was flattened by the quake.

"We share your pain, we have lost our own children, we are going to try to rebuild Bam, but this time more solidly," Khamenei told survivors.

Police and soldiers were deployed in force throughout Bam after looters attacked convoys bringing in essential supplies.

"The security situation has much improved with the arrival in town of a large number of police and soldiers," said policeman Ali Chehrazi.

Hundreds, if not thousands of soldiers, elite Revolutionary Guards and Bassiji volunteer militiamen, touting Kalashnikov rifles and automatic pistols, patrolled the streets or stood guard at key intersections.

This followed a day of looting, attributed by some to villagers from outlying areas spared by the earthquake, of badly needed humanitarian supplies.

At Bam airport, planeloads of aid continued to arrive from abroad, but German rescue teams were preparing to return home Tuesday because there was little hope of finding further survivors.

"The team and the sniffer dogs are exhausted," Heinrich Ganss, spokesman for the volunteer organization Technisches Hilfswerk (THW), said in the western city of Darmstadt.

A UN spokesman in Geneva said that "short of a miracle," there was no expectation of finding many more survivors.

The first US flight to Iran since the hostage crisis ended in 1981, carrying emergency aid to Bam, will be followed by more, the US Air Force combined air operation centre in the Gulf state of Qatar said.

Colonel Bret Klassen, a US Air Force logistician, said: "I think it's a great opportunity to open up dialogue. It's unfortunate that it's under these circumstances with such a large loss of life."

However in Washington, State Department spokesman Lou Fintor said: "there is no political angle here.

"Our efforts will not alter the tone or intensity of our dialogue with the Iranians on other matters of grave concern," he added, referring to US allegations that Iran supports terrorism and is seeking nuclear weapons.

Meanwhile, finance and economy ministers of the Gulf Cooperation Council (GCC) states were to hold an extraordinary meeting in Riyadh on Monday night to coordinate sending more aid to Bam's earthquake victims.

The United Nations, whose agencies have already pledged about half a million dollars (400,000 euros) to fund relief efforts, said that cash donations were desperately needed.

"The assessments we have been doing so far is to assess the needs of today but we have to think about tomorrow and the week after tomorrow and two or three months after tomorrow," said Rashid Khalikov, deputy director of the UN Office for the Coordination of Humanitarian Affairs (OCHA).

Representatives from donor countries had met in Geneva with UN agencies and officials from the international Red Cross to discuss the disaster and how best to respond, Khalikov told reporters.

Even cash-strapped neighbouring Afghanistan has donated 150,000 dollars, a spokesman for President Hamid Karzai said in Kabul.

TERRA.WIRE