The British Museum in London has sacked a member of staff and police are investigating after treasures were reported "missing, stolen or damaged".
Items including gold, jewellery and gems of semi-precious stones were among those missing from the museum, one of the UK's largest tourist attractions.
The majority of the items were kept in a storeroom, the museum said.
British Museum director Hartwig Fischer said the museum would "throw our efforts into the recovery of objects".
He added: "This is a highly unusual incident. I know I speak for all colleagues when I say that we take the safeguarding of all the items in our care extremely seriously.
"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."
Legal action would be taken against the staff member who was fired, the museum added.
The Economic Crime Command of the Metropolitan Police is investigating but no arrests have been made.
The British Museum has also started an independent review of security.
None of the items, which dated from the 15th Century BC to the 19th Century AD, had recently been on display and were kept primarily for academic and research purposes, the museum said.
The PA news agency said it understood the items were taken before 2023 and over a "significant" period of time.
George Osborne, chair of the British Museum, said: "The trustees of the British Museum were extremely concerned when we learnt earlier this year that items of the collection had been stolen."
He added: "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."
Mr Fischer added the organisation had "brought an end to this", and was "determined to put things right".
Latest Stories
-
I’m proud that despite all the challenges, we have maintained Free SHS – Akufo Addo
2 hours -
Alan’s running mate, KOD says GRASP will revolutionize care for the Elderly in rural areas
2 hours -
Election 2024: Alan paints Accra yellow as the crowd marches through the capital with him
2 hours -
Vacant seats: Speaker has not done what would have led to greater peace – Kofi Bentil
2 hours -
Police on manhunt for Adabraka daylight robbers
2 hours -
Lordina Mahama presents medical supplies and equipment to Tishigu Health Center
3 hours -
Lordina Mahama urges Ghanaians to prioritise regular health screenings
3 hours -
EC to reassess decision on presidential ballot printing next week – Dr Bossman Asare
3 hours -
Shark attacks surfer, 61, on Hawaiian island of Maui
3 hours -
29 Nigerian children may be sentenced to death for protesting against cost-of-living crisis
3 hours -
Nigerian becomes first black woman to lead major political party in the UK
4 hours -
Perception issues affecting Supreme Court – Nii Armah Addy
4 hours -
Armed men bolt with cash at Adabraka market in dramatic daylight robbery
4 hours -
Bawku Conflict: National Security fully aware of events – Bawku Naaba’s lawyer
4 hours -
Dodome to celebrate festival in a bid to construct traditional council facility
4 hours