Egyptian media say prosecutors have referred eight museum employees for trial over the botched reattachment of the beard on the burial mask of the pharaoh, Tutankhamun.

It comes a year after officials opened an investigation into how the blue and gold braided beard came to be detached and then hastily glued back on.

The accused face charges of negligence and violating professional standards.

The 3,000-year-old artefact is one of Cairo's biggest tourist attractions.

Conservators at the Egyptian Museum had given differing accounts of the circumstances of the beard becoming detached.

One suggestion was that it had been knocked off accidentally, another that it had been removed after becoming loose.

Prosecutors said workers then "recklessly" tried to cover up the mistake, using large amounts of inappropriate glue in an effort to fix it.

In all, they made four attempts to reattach the beard, on the later three occasions also trying to remove evidence of their earlier failed efforts.

One report, in the Daily News Egypt, quoted prosecutors as saying: "Ignoring all scientific methods of restoration, the suspects tried to conceal their crime by using sharp metal tools to remove parts of the glue that became visible, thus damaging the 3,000-year-old piece without a moment of conscience."

Those due to face trial include a former director of the museum and a former director of restoration.

Last October, a team of conservators led by German experts began work to remove the damage and reattach the beard professionally.

Following successful restoration, the mask was put back on public display in December.