People in Leeds must make a “collective effort” to avoid further coronavirus restrictions, councillors have warned.
The city is expected to be added to Public Health England’s weekly watch list as an “area of concern” after its infection rate rose to 29.4 cases per 100,000 people.
If cases continue to rise, more stringent measures could be imposed.
City council leader Judith Blake said it was “a pivotal moment in our efforts to control the spread of the virus”.
“Nobody wants to see further restrictions on life in Leeds,” she said.
“The harsh reality is that if our infection rate continues to rise as it has been, we will be left with no alternative”.
According to recent figures, 44 new coronavirus cases were identified in Leeds on Wednesday.
Other parts of West Yorkshire have been subject to tighter coronavirus restrictions for several weeks.
Leeds, unlike neighbouring Bradford, had avoided the controls because its infection rates were much lower.
But the city council said cases had been rising in parts of the city.
As an area of concern, Leeds will be subject to increased monitoring and could face additional measures if infection rates do not fall.
The authority has urged people to follow guidance on social distancing, hand-washing, and wearing face masks.
It further reminded those with symptoms of the virus to remain at home.
The council’s public health director Victoria Eaton said it was “imperative we do all we can to contain the spread of this virus and protect one another at this crucial time for the city”.