The British Museum has dismissed a member of staff after items from its collection were found to be "missing, stolen or damaged," the museum said in a statement on Wednesday.

The items included gold jewelry and gems of semiprecious stones and glass dating from the 15th century B.C. to the 19th century A.D., the museum said.

None of the items in question had been on public display recently and the majority were "kept in a storeroom belonging to one of the museum's collections," according to the statement.

"This is a highly unusual incident," said Hartwig Fischer, director of the museum.

"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," Fischer said, noting that the museum apologized for what had happened.

The museum said it would take legal action against the member of staff who was fired, and the matter is now being investigated by the Economic Crime Command of the Metropolitan Police.

It has also launched an independent review of security to look into the incident and to provide advice regarding the museum's security arrangements in the future. The review will start and support a program to recover the missing items.

Founded in 1753, the British Museum has a collection of about eight million objects covering two million years of human history.