The National Crime Agency (NCA) has confirmed it has received information about allegations of modern slavery and exploitation in Leicester's textile industry.
It said it is looking at the information and working with organisations including Leicestershire Police, HM Revenue & Customs, Leicester City Council, the Health and Safety Executive and Home Office Immigration Enforcement.
A spokesman for the agency said their "primary focus" was protecting vulnerable people and that visits to a number of businesses in Leicester are "likely to continue".
"The NCA does not intend to give a running commentary on our activity, but once our assessment is complete we will look to engage with partners to deliver a response at the appropriate level," the spokesman added.
A HSE spokeswoman said it had inspected 10 sites. She said one business was issued an improvement notice and officers will "take enforcement action where necessary".
The fashion brand Boohoo, that has suppliers in Leicester, has today ordered an independent review of its UK supply chain following reports of poor working conditions at a factory in the city.