Scientists from the UK's Newcastle University say they have successfully created hybrid embryos derived from human cells and a cow egg.

The team, led by Dr Lyle Armstrong, presented preliminary data to a conference in Israel last week but stressed that the results are only preliminary and have yet to be validated by the peer review process.

In a statement, the university said the embryos were created from one of its human embryonic stem cell lines, Ncl-1. The human cells were injected into an enucleated cow egg, which was then encouraged to divide. The team said the hybrid embryos survived for three days.

The university's Professor John Burn told the BBC that the team now had "preliminary data which looks promising but this is very much work in progress".

He said the next step was to "get the embryos to survive to around six days when we can hopefully derive stem cells from them".

Armstrong and his co-researcher Dr Majlinda Lako have a licence from the UK's Human Fertilisation and Embryology Authority (HFEA), granted in January, to conduct the research.

The UK Parliament will debate next month further regulation of the research under its Human Fertilisation and Embryology Bill.

Under the current law, any hybrid embryos created have to be destroyed at 14 days.