Thieves have stolen "valuable and culturally significant" Chinese works of art from a Cambridge museum.
The 18 items, mostly jade and from the Fitzwilliam Museum's permanent collection, are believed to be worth millions of pounds.
Cambridgeshire Police said a group of people were involved in the break-in at about 19:30 BST on Friday.
A University of Cambridge museum spokesman said a thorough investigation of security measures is under way.
"These works are a highly important part of our collection and their loss is a great blow," he said.
Forensic examinations have been carried out at the scene and CCTV footage is being examined.
Police patrols have also been increased in the area around the museum.
A spokeswoman for Cambridgeshire Police said the haul is thought to be worth "millions of pounds".
Det Ch Supt Karen Daber, leading the investigation called Operation Tundra, said a team of detectives was working closely with staff at the Fitzwilliam, the principal museum of the University of Cambridge.
"The items stolen are very valuable and are of great cultural significance, so we are absolutely committed to recovering them and bringing those who stole them to justice," she said.
"In particular, we are keen to hear from anyone who may have been in or around the Fitzwilliam Museum between 6pm and 8pm and may have heard or seen anything unusual or suspicious.
"While this is an exceptional crime that we are taking very seriously, it is also worth remembering that this type of offence is extremely rare.
It follows a theft at the Oriental Museum at Durham University where Chinese jade and porcelain items were stolen.
They have since been found and five people have been arrested and questioned about the raid.
Mrs Daber refused to speculate on whether the two thefts were linked.
Among the stolen items in Cambridge were six pieces from the Ming dynasty, including a jade 16th Century carved buffalo, a carved horse from the 17th Century and a green and brown jade carved elephant.
A jade cup and vase which is carved with bronze designs was also stolen along with an opaque jade brush washer.
Eight pieces from the Qing dynasty were taken, and a table screen from the Qianlong period and a jug and vase from the 18th Century make up the rest of the stolen items.
Their exact value has not been released.
A university spokesman said the museum had a policy of not attaching monetary values to artefacts in its collection.