The government has written to care home providers in England to warn them of a rise in new coronavirus infections within the sector.
A letter from the Department of Health urged care bosses to take "necessary action to prevent and limit outbreaks". Cases were mainly among staff but risked spreading to residents, it said.
It comes as a further 3,330 positive cases were recorded in the UK - the third consecutive day in which cases have been over 3,000. It brings the total number of confirmed cases to 368,504.
Friday's letter from the Department of Health and Social Care said testing data had revealed an increase in the number of positive results in care homes and called on the care sector to work with the government.
"You will know already that we are experiencing a rise in confirmed Covid-19 cases across the UK population," wrote Stuart Miller, director of adult social care delivery.
"I need to alert you to the first signs this rise is being reflected in care homes too."
"I am writing at the earliest opportunity, so we can work in partnership to prevent further spread of the disease. The rapid flow of data and information, to and from care providers, is vital to this effort."
Mr Miller said the infections had been detected chiefly among staff but had been transmitted to residents in some cases. He went on to stress "the importance of regular testing and consistent use of PPE".
Source: BBC News, 14 September 2020