The Taoiseach has warned that there's "every chance" other counties could face extra coronavirus restrictions - but said it's not inevitable.
Donegal this evening became the second county to be moved to level three, after the stricter measures were also imposed on Dublin last week.
Micheál Martin said officials are 'very closely' monitoring the situation in Louth, Waterford, Wicklow, Kildare, Cork and Galway.
He said: "The growth of the virus isn't limited to Donegal and Dublin - the information provided to us by NPHET this evening tells us that nationwide we have seen a deterioration over the course of the past week.
"Last week, I announced additional restrictions on Dublin, and tonight it is Donegal. But if we're honest, there's every chance we could have similar announcements in other areas.
"Each and every one of us literally has to decide in our own lives and in the decisions we make whether this virus is going to be given the space to grow. While there is every chance will have to move to level three, there is nothing inevitable about it."
Situation can change 'very rapidly'
Acting Chief Medical Officer Dr Ronan Glynn, meanwhile, said there's been 'some stabilisation' in the numbers in Louth and Waterford in recent days.
However, he warned that the situation in Donegal shows the situation can 'change for the worse very rapidly'.
He said: "I do not want to be back here next week or the week after having had to make recommendations with NPHET in relation to other counties."
Dr Glynn said everyone needs to cut down their number of social contacts - suggesting the most important number for each individual is the number of people they've met today.
He said occasions such as Communions and Confirmations are 'part of the problem', but are not alone in driving the increase in cases.
He explained:"There are significant birthdays... neighbours going to other houses for a couple of drinks.
"It's any type of household gathering and inter-household mingling that gives this virus an opportunity to transmit."
Dr Glynn said everyone has to make 'small sacrifices', such as cutting out some of their planned social activities to limit the number of people they socialise with.
