Experts have for the first time created cloned embryos from an adult monkey - a technical breakthrough that could bring efficient human cloning a step closer.

A team in the US created dozens of cloned embryos from a 10-year-old male macaque, the BBC reported, citing the journal Nature.

This could make it easier to clone human embryos for use in research.

It raises the prospect of developing transplant tissues to treat diseases such as diabetes and Parkinson's that will not be rejected by the body.

The American group was able to extract stem cells from some of the cloned monkey embryos, persuading them to develop into mature heart and nerve cells in the laboratory.

Other scientists have welcomed news of the advance. Robin Lovell-Badge, a UK stem cell scientist at the National Institute for Medical Research in Mill Hill, near London, said: 'Although this work has not been published yet, it is potentially significant.

'There has been a worry that primates may prove to be difficult in terms of cloning.'

This would have been a huge setback for researchers working to develop new medical therapies based on embryonic stem cells.

In cloning to obtain stem cells, DNA from an adult animal is inserted into an unfertilised egg that has had its own genetic material removed. The egg is then encouraged to grow into an early embryo, from which stem cells can be extracted.