Two people were arrested and five women were taken away from a guest house by police investigating alleged sexual exploitation.
Twenty officers raided the Athena Guest House in Cowley Road, Oxford, last night following a tip-off of possible prostitution and sexual exploitation.
The five women who were taken from the guest house were being supported by specially-trained officers, Thames Valley Police said.
A 45-year-old man and a woman were held on suspicion of intentionally arranging or facilitating entry into the UK of a person to engage in sexual exploitation.
Sgt Neil Applegarth, of the East Oxford neighbourhood team, said: "Officers attended the guest house at 8pm after receiving some information relating to the possible exploitation of women.
"We are in the very early stages of this investigation and so I ask if anyone has any information to contact us immediately."
According to its website, the guest house is based within a red-brick Victorian house with "lots of charm and atmosphere" and has a three-star AA rating.
Prices start from £48 for a double room with en-suite up to £118 for a family room with en-suite, including a double bed and two single beds.
The multi-agency raid was carried out under Section 8 of the Police and Criminal Evidence Act 1984, a police spokesman said.
Professionals from Oxford City Council, the multi-agency Kingfisher unit, based at Cowley police station, and the Elmore Independent Trauma Adviser Team also attended.