RAIDS are taking place across Essex and other counties to find items stolen from auction houses and museums.
A series of warrants are being executed by hundreds of officers from 26 police forces, led by the serious organised crime agency.
Today’s action follows six crimes which took place over a four-month period last year at museums and auction houses across England.
Chinese artefacts and rhinoceros horn were stolen in six incidents and several high value items are still missing.
Eight people have already been convicted and jailed for more than 40 years.
Exact locations have not yet been revealed for operational reasons.
Chief Constable Mick Creedon, who is leading the investigation for the Association of Chief Police Officers, said: “Today’s operation follows a long and complex pan-European investigation.
“The series of burglaries last year had a profound effect on museums and similar institutions and we are committed to bringing all those who were involved in the conspiracy to justice.
“Many of the stolen Chinese artefacts are still outstanding and a substantial reward remains on offer for information which leads to the safe return of those priceless items.”
Anyone with information that they believe could lead to tracing the stolen property can call 01733 863157 or 01483 229198 quoting “7028/END” or 08703 120535.