Video report by ITV News Correspondent Martha Fairlie
Leeds, South Tyneside, Corby, Middlesbrough and Kettering have all been added to the watchlist as areas of concern, the Health Secretary has confirmed.
It comes as it was announced restrictions in Greater Manchester and Leicester would be eased from September 8.
Identified by Public Health England as areas with higher than average incidences of Covid-19, Leeds has been added to the watchlist alongside South Tyneside, Corby, Middlesbrough and Kettering.
Norfolk, Rossendale, and Northampton have all been classed as areas in need of "enhanced support" due to rising cases - with measures like increased testing likely to come into force.
Prior to the announcement on Leeds, the city council said that while being on the list would not mean further restrictions would be brought in at this stage, it would mean increased monitoring of cases and could see additional steps taken in the future.
The latest seven-day infection rate shows Leeds as having 29.4 cases per 100,000 people, with 44 new cases today identified on Wednesday and a testing positivity rate of 4.2%.
Ms Blake said: “This is a pivotal moment in our efforts to control the spread of the virus in Leeds and to keep our city open.
“Nobody wants to see further restrictions on life in Leeds and we want to assure everyone that we’re doing absolutely everything within our power to avoid that happening.
“But the harsh reality is that if our infection rate continues to rise as it has been, we will be left with no alternative.
“With that in mind, now more than ever we need a collective effort from the people of Leeds who have shown so much resilience and civic pride throughout this crisis".
Ms Blake added that there were a range of factors behind the rise in cases. Seven fines were issued over the bank holiday weekend to organisers of illegal events.
“It’s up to us all to keep our families, friends and neighbours safe and to play our part in keeping Leeds’s recovery going,” she said.
The council has reminded people to isolate if anyone in their household is showing Covid-19 symptoms, to keep social distancing, wear a face covering and to wash hands regularly.
Victoria Eaton, Leeds City Council's director of public health, said: "It's imperative that we do all we can to contain the spread of this virus and protect one another at this crucial time for the city."