The remains were discovered at a height of 6,700 metres (22,000 ft) on Mount Llullaillaco, a mountain in northwest Argentina near the border with Chile.

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"They appear the best preserved of any mummy I've seen," said archaeologist Dr Johan Reinhard, who helped lead the team that found the mummies.

"The arms looked perfect, even down to visible hairs."

Dr Reinhard said the bodies may have been frozen since they were left on the mountain by Incas.

Even though they are buried under about 1.5 metres (5 ft) of rock and earth, their internal organs look perfect on a CT scan - as if they had died only recently.

A statuette of a llama found with the children

How these children died has yet to be established.

Inca gods

Their burial platform carried other sacrifices, apparently to Inca gods. These included 35 gold, silver and shell statues, pottery containing food, and articles of clothing including moccasins. All are in excellent condition.

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"The undamaged female has a beautiful, yellow, geometrically-designed cover laid over her outer mantle," said Dr Reinhard, a senior research fellow at the Mountain Institute in West Virginia.

US, Argentine and Peruvian scientists worked together on the expedition, organised by National Geographic.

Dr Reinhard, who has found several other mummies, said his team had battled snow and high winds to reach the site.

"At one point we had to lower one of our workers into the pit by his ankles so he could pull the mummy out with his hands," he said.