There may be some life left yet for the woolly mammoth, according to controversial research by Russian and South Korean scientists that has raised hopes the extinct animal could be cloned.

The team of researchers from Russia and South Korea said they had discovered mammoth tissue fragments buried under metres of permafrost in eastern Siberia that could contain living cells.

The existence of the cells -- perhaps too few to achieve successful cloning, and treated with scepticism by many stem cell scientists -- must still be confirmed by a South Korean lab.

But expedition member Sergei Fyodorov of Russia's Northeastern Federal University said the discovery in the far north of the vast Yakutia region of eastern Siberia could soon lead to actual woolly mammoth cloning attempts.

"We discovered the mammoth tissue fragments in eastern Siberia in early August," Fyodorov told AFP in a telephone interview Wednesday.

"It seems that some of the cells still have a living nucleus. We saw that with portable microscopes on the spot -- the cells appeared in colour," said the scientist.

The mission has struggled for credibility amid doubts that permafrost could keep anything alive for millennia and eventually give humans a chance to recreate extinct animals that once roamed the planet.

One of the participants in the expedition was the hugely controversial South Korean cloning pioneer Hwang Woo-Suk of South Korea's Sooam Biotech Research Foundation.

Hwang was a national hero until some of his research into creating human stem cells was found in 2006 to have been faked. But his work in creating Snuppy, the world's first cloned dog, in 2005, has been verified by experts.

Russia's state-run RIA Novosti news agency cautioned in a commentary that "the cloning of mammoths is being indefinitely postponed" because the find -- whatever it may have contained -- was too small.

The mammoths are believed to have vanished fewer than 4,000 years ago -- a flash in geological terms that coincided with the rise of the Bronze Age in Egypt.

Scientists set their sights on the animal after global warming thawed parts of Siberia, raising hopes a mammoth could be cloned using technology like that used in Scotland in 1996 to produce a cloned sheep called Dolly.

The same Russian researchers went on their first woolly mammoth hunt with a team from Japan in the late 1990s and found traces of skin that turned out to have belonged to a rhinoceros.