SCIENTISTS have successfully produced the world's first monkey clones using the same method that made Dolly The Sheep.

Zhong Zhong and Hua Hua are just eight and six weeks old respectively, and early images of the pair are incredibly cute – but animal welfare experts speaking to The Sun have condemned plans to create more clones for drug-testing as a "horror show".

8 Zhong Zhong and Hua Hua are now just a few weeks old Credit: PA:Press Association

Dr David King, from the Human Genetics Alert lobby group, said: “We are concerned that this is a stepping stone to the creation of human clones.

“Although it looks technically difficult, those with enough financial resources and the ambition to be the first to create a cloned child are likely to try.”

The genetically-identical long-tailed macaques were born at Shanghai's Chinese Academy of Sciences Institute of Neuroscience.

They're unique because they're the first primates to be cloned using the somatic cell nuclear transfer technique that was used to create the famous sheep-clone Dolly 20 years ago.

8 The genetically identical monkeys are the first to be created using the decades-old 'Dolly the Sheep' method Credit: PA:Press Association

Senior author Dr Qiang Sun said: "We tried several different methods, but only one worked."

"There was much failure before we found a way to successfully clone a monkey."

The first monkey ever cloned was called Tetra, who was born in 1999 through a simple method called embryo splitting.

This is a very similar approach to how twins naturally occur, but only four offspring can be created at at a time.

8 Scientists hope to create even more clones for drug-testing experiments Credit: AP:Associated Press

For Zhong Zhong and Hua Hua, scientists removed the nucleus from an egg cell and replaced it with another nucleus from body cells.

This reconstructed egg eventually turns into a clone of whatever donated the second nucleus.

The two baby monkeys, which are currently being bottle-fed, will now be monitored for their physical and mental development.

The research term behind the incredible feat are now planning to create more macaque clones over the coming months.

8 Animal rights experts told The Sun that cloning causes 'unimaginable' suffering Credit: PA:Press Association

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But worryingly, the scientists say they now want to create "customisable" populations of monkeys for large-scale animal testing.

Sun explained: "There are a lot of questions about primate biology that can be studied by having this additional model."

"You can produce cloned monkeys with the same genetic background except the gene you manipulated."

"This will generate real models not just for genetically based brain diseases, but also cancer, immune, or metabolic disorders and allow us to test the efficacy of the drugs for these conditions before clinical use."

8 Scientists who led the project say they follow 'strict ethical standards' Credit: PA:Press Association

Speaking to The Sun, Dr Julia Baines, Science Policy Adviser for animal rights organisation PETA UK, warned over the horrors of cloning.

"Experimenters constantly receive funds to perform monstrous experiments on animals, and cloning monkeys is the latest Frankenscience that PETA condemns."

"Cloning is a horror show: a waste of lives, time and money – and the suffering that such experiments cause is unimaginable."

"Because cloning has a failure rate of at least 90%, these two monkeys represent misery and death on an enormous scale."

8 PETA: Cloning "serves only to increase animal suffering" Credit: AP:Associated Press

"This experiment – and all other experiments on animals – should be ended immediately," she added.

Baines said that cloning primates "will not solve medical problems, but will lead to misery for these intelligent and sensitive beings".

The Sun also spoke to animal welfare charity RSPCA spokesperson Penny Hawkins, who warned that there are "huge ethical and animal welfare concerns about this".

"These are living animals, not just research tools," the RSPCA's senior scientist explained.

8 Dr David King, from Human Genetics Alert is concerned that we are a step closer to cloning humans

"If you look at the wording of the report, a lot of animals were killed in order to achieve the live births.

Some actually died shortly after birth which would cause huge suffering to them and their mums."

According to Hawkins, over 100 million animals are subject to lab experiments each year, including four million in the UK.

"Most are used to develop and test medicines. They're also used to do safety assessments of chemicals and other substances."

8 Macaques Zhong Zhong and Hua Hua were cloned using the same methods used with Dolly the sheep Credit: PA:Press Association

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The scientists involved in the project say that the lab is following strict international guidelines for animal research that have been set by the US National Institutes of Health.

Study co-author Dr Muming Poo said: "We are very aware that future research using non-human primates anywhere in the world depends on scientists following very strict ethical standards."