The British Museum has announced items from its collection were found to be missing, stolen or damaged.
The London museum, which houses artefacts from around the world, has launched an independent review of security as it said a staff member at the institution has been dismissed.
The matter is also under investigation by the economic crime command of the Metropolitan Police.
The museum’s director Hartwig Fischer apologised for the missing artefacts, explaining “we are determined to put this right” and ready to “throw our efforts into the recovery of objects”.
Chair of the museum, George Osborne said the trustees were “extremely concerned” by the incident and “used all the disciplinary powers available to us to deal with the individual we believe to be responsible”.
The items reported stolen, missing, or damaged include gold jewellery and gems of semi-precious stones, and glass dating from the 15th century BC to the 19th century AD.
The museum described these as small pieces which hadn’t been on public display recently, and were mainly used for research and academic work.
A spokesperson for the Met Police said their investigations are ongoing and no arrests have been made, but declined to provide any further information.
Mr Fischer said: “The museum apologises for what has happened, but we have now brought an end to this – and we are determined to put things right.
“We have already tightened our security arrangements and we are working alongside outside experts to complete a definitive account of what is missing, damaged and stolen. This will allow us to throw our efforts into the recovery of objects.”
Mr Osborne outlined key priorities for its trustees include recovering the missing objects and taking steps to ensure an incident like this does not happen again.
Mr Osborne said: “The trustees of the British Museum were extremely concerned when we learnt earlier this year that items of the collection had been stolen.
“The trustees have taken decisive action to deal with the situation, working with the team at the museum.
“We called in the police, imposed emergency measures to increase security, set up an independent review into what happened and lessons to learn, and used all the disciplinary powers available to us to deal with the individual we believe to be responsible.
“Our priority is now threefold: first, to recover the stolen items; second, to find out what, if anything, could have been done to stop this; and third, to do whatever it takes, with investment in security and collection records, to make sure this doesn’t happen again.
“This incident only reinforces the case for the reimagination of the museum we have embarked upon. It’s a sad day for all who love our British Museum, but we’re determined to right the wrongs and use the experience to build a stronger museum.”
The incident comes days after a man was stabbed while waiting in a queue outside the world-famous tourist attraction in London.
Police officers responded to reports of a knife attack near the museum on 8 August, with an eyewitness recalling seeing “a pool and trail of blood” on the ground.
Witnesses described how the middle-aged male victim, who was stabbed in the arm, “dripping blood everywhere” along the busy street while trying to escape.
He was treated at the scene before being taken by the London Ambulance Service to a hospital.
Additional reporting on agencies.