The confirmed death toll passed the 20,000 mark, Interior Minister Abdolvahed Mussavi Lari said.

"Unfortunately, the number of dead now tops 20,000 and about 15,000 bodies have already been buried," the minister was quoted as saying by state television, without giving a number for the wounded.

Some 11,500 injured survivors have been flown to hospitals around the country for treatment, a spokesman for the ministry said.

The search for survivors was expected to end on Sunday and there was no need to rush more international rescue teams to the area, the United Nations said in Geneva.

"It is anticipated that the search and rescue operations will be over today," a statement from the UN Office for the Coordination of Humanitarian Affairs said.

A UN spokesman in Geneva said any further search operations would be handled by more than a dozen international teams already working in the area with Iranian officials.

But he said that "short of a miracle," there was no expectation of finding many more survivors.

Meanwhile, the state IRNA news agency reported that some 1,000 people had been pulled alive from the ruins on Saturday and Sunday.

Those rescued were located thanks to the "sniffer dogs and hi-tech ultrasound equipment of both Iranian and foreign emergency teams", the news agency said.

Since Saturday, mechanical diggers have been bulldozing a former wasteground on the western edge of this pulverised city, burying hundreds in mass graves.

Relatives knelt at the side of the mass graves, some with their hands and heads bowed down in the dust, paralysed in grief over the loss of loved ones.

In the span of just 100 metres (yards), one AFP correspondent saw about 300 to 400 bodies piled up, wrapped in white cloth and blankets, others rolled in carpets.

Most of the dead were adults, but there was one row of babies wrapped in blankets.

On the ground, freezing night-time temperatures over the past 48 hours and the disorganization of the relief effort in the face of the massive casualty toll left little hope of further survivors being found.

Ari Vakkilainen of Finn Rescues, a Finnish government international rescue organization, told AFP: "I think there are not many people still alive under the rubble because of the way the buildings here are made."

The bricks generally used in Bam buildings are made of baked mud that turn to dust and sand when buildings collapse, which means there are not many air pockets.

"Even with a good air pocket, 72 hours is about the absolute maximum that somebody can survive under the rubble," said Vakkilainen, who is a fire chief in his regular job.

Rescue teams from Switzerland, Turkey, Germany, Britain, Italy, Luxembourg, Finland, Azerbaijan, Spain, Ukraine and Poland were among the first to touch down here in response to Iran's calls for international aid, he said.

But giving a very downbeat assessment of the chances of finding survivors, he said: "The problem is, there's only a total of 30 sniffer dogs here already which are working."

Iranian President Mohammad Khatami, whose country has waived visa restrictions for relief workers and foreign journalists, said Saturday he would visit Bam on Sunday or Monday, and ordered rescue efforts to be speeded up.

IRNA reported that a first US plane bringing aid workers and medical material for rescue operations in Bam, a giant Hercules C-130, arrived at 3 am Sunday (2330 GMT Saturday) in nearby Kerman.

As soon as news broke early Friday of the quake which claimed tens of thousands of lives, US President George W. Bush sent his condolences to the Iranian people and announced aid to the victims.

Shortly afterwards an Iranian official announced that his country would accept aid from all countries except Israel, which Iran does not recognize.

Iran and the United States broke off diplomatic relations after the Islamic revolution in 1979 and the taking of American hostages in the Tehran embassy.

The International Committee of the Red Cross said it had 35 tonnes of medical supplies, tents, blankets and bedding loaded in Jordan and ready to shuttle to southeastern Iran from Monday.

TERRA.WIRE