Tighter lockdown restrictions could be introduced in Blackburn following a spike in coronavirus cases.
People in the town will be asked to limit visitors from another household to two, compared with looser rules elsewhere.
The area’s public health director said stronger measures would be imposed in two weeks if the number of cases did not fall.
Mass testing began at the weekend after 61 new cases sprang up within a week.
Figures show Blackburn with Darwen now has 41 new cases per 100,000, up from 29.5.
Leicester, where a local lockdown has been imposed, has seen the rate fall from 156.8 in the seven days to 26 June, to 114.3 in the seven days to 10 July.
The second highest rate is in Pendle, Lancashire, where it has gone up from 14.2 to 67.8.
Director of public health for Blackburn with Darwen, Prof Dominic Harrison, said there would also be “targeted work” after a rise in infections within the South Asian community.
He said there had been “cluster infections”, particularly with “families in small terraced houses”.
Prof Harrison said that when “one person gets infected in a multi-generational household, all the household members are getting infected”.
He warned: “If the numbers aren’t coming down within a two-week period, we will probably need to go into a reversal of some of the lockdown measures.”
Information videos are being produced in English, Urdu and Gujurati to spread the message in the former mill town.
“One of the things we don’t want to do is to get in a situation like Leicester where everything is open to where everything is shut,” Prof Harrison said.
Faz Patel, from the Lancashire council of Mosques, remarked that “young people are going out not realising they can be carriers and then going back home to see their elderly parents”.