Nicola Sturgeon confirmed that the lockdown will be continued in Scotland for three weeks - and warned that dropping the "stay at home" message would be "catastrophic".
The SNP leader insisted that "extreme caution" was required at this "critical juncture".
Speaking at her daily briefing from the Scottish Government's headquarters in Edinburgh, she said: "Our assessment of the evidence leads me to the conclusion that the lockdown must be extended at this stage."
Ms Sturgeon insisted she would "not be pressurised" into lifting measures prematurely following reports that Prime Minister Boris Johnson will announce some easing of restrictions.
She explained she did not want to lift restrictions too early and risk a potential second spike of coronavirus.
The Scottish First Minister said: "The decisions we take now are a matter of life and death and that is why they weigh so heavily."
"I particularly strongly believe for us to drop the clear, well-understood stay at home message right now could be a potentially catastrophic mistake."
Boris Johnson's spokesperson has announced that his statement on the route out from lockdown will begin on 7pm on Sunday.
Any changes to the UK lockdown this Monday will be "very limited" and could be reversed if the virus spikes, No10 said.
The Prime Minister's official spokesman said: "Throughout we have said we would take a four-nation approach and we believe that provides the best way forward.
"The four nations entered the restrictions at the same time and should, where it makes sense, exit the restrictions at the same time."
"We agree that the only circumstances where there should be divergence is when there is evidence that supports it."
Before restrictions could be lifted, Sturgeon said the Scottish Government wanted to see data confirming "a very clear downward trend".
And she insisted: "The way in which we emerge from lockdown that wee bit more quickly is to stick with the current restrictions now."
The First Minister said: "There are still significant numbers of people in Scotland infected with this virus and we're not yet confident that the all-important R number is comfortably below one."
The R number measures the number of people that each person with coronavirus infects with the disease, with Ms Sturgeon saying this "could still be hovering around one just now".
And she added this "means that any significant easing up of restrictions at this stage would be very, very risky indeed".
There are also suggestions the R number in Scotland could be a "bit higher" than other parts of the UK, she added, "perhaps reflecting the fact that our first cases came later than England so we might be at a different and slightly later stage of the infection".
She told Scots: "In particular I want to see what our estimates of cases and the R number look like a week from now."
The lockdown restrictions will be reviewed again in three weeks' time, she added.
But she said: "We can make changes to the regulations before then if the evidence suggests it is safe to do so."
