Thames Valley Police executed warrants in Redbridge Hollow in Hinksey Hill and elsewhere in Oxford
Ten people have been arrested in anti-slavery raids in Oxford.
About 150 officers executed warrants in Rose Hill, Blackbird Leys and at a travellers' site in Redbridge Hollow in Hinksey Hill, at about 06:00 GMT.
The investigation, known as Operation Rague, relates to human exploitation, slavery and fraud offences.
Nine men and one women were arrested on suspicion of offences including servitude and slavery, assault, making threats to kill and fraud, police said.
Supt Andy Boyd, of Thames Valley Police, said the "alleged offences are matters which are taken extremely seriously".
Police executed warrants at about 06:00 GMT
"Our priority at this time is to care for those individuals who have been subject to these offences.
"At this time we are caring for those individuals with our colleagues in the local health service and the local authority," he said.
A 44-year-old woman and a man aged 56 were arrested on suspicion of servitude and slavery
A 44-year-old man was arrested on suspicion of making threats to kill and exploitation offences
A 47-year-old man was arrested on suspicion of servitude and slavery, assault, and making threats to kill
A 44-year-old man was arrested on suspicion of trade offences
Two men, aged 20 and 44, were arrested on suspicion of fraud
Three more men, aged 18, 19, and 27, were also arrested in connection with the operation
Thames Valley Police worked with a number of organisations including the National Crime Agency's UK human trafficking centre, local councils, HM Revenue and Customs and the Salvation Army.
Extra officers were put on patrol in the areas of the raids.
Nine men and one woman were arrested in the raids
About 150 police officers took part in the operation
