Nine people have now been arrested in connection with a child exploitation investigation.
Initially six men were arrested on suspicion of conspiracy to commit sexual activity with a child.
That number has now risen to nine after officers arrested three more men in the early hours of Saturday (April 7) morning.
All nine have now been released on police bail.
A spokesman from Derbyshire Constabulary said: "The arrested men are aged between 20 and 47. Eight are from Derby, while one is from out of the county.
"The investigation is still in its early stages."
As part of the operation, there will be an increased number of officers in the community over the coming days.
Superintendent Tracy Harrison said: “Our officers will be out in the community to offer reassurance to people living in the area.
“I would encourage anyone who has any concerns or wants to talk about issues in their neighbourhood to go up and have a chat with the officers.
“Similarly, if anyone has any information they feel might be of assistance to our investigation, they can speak to an officer, phone us on 101, or call Crimestoppers anonymously on 0800 555 111.”