Speaking in Holyrood, the first minister did not rule out the further relaxation of rules – moving to Level 0 – on 28 June but said the Scottish government wanted to “buy ourselves sufficient time” to allow the vaccination programme to continue its work.
She suggested that Scotland would not return to “much greater normality” until later in July at the earliest.
“Given the current situation – and the need to get more people fully vaccinated before we ease up further – it is reasonable to indicate now that I think it unlikely that any part of the country will move down a level from 28 June,” Ms Sturgeon said.
“Instead, it is likely that we will opt to maintain restrictions for a further three weeks from 28 June and use that time to vaccinate – with both doses – as many more people as possible.
“Doing that will give us the best chance, later in July, of getting back on track and restoring the much greater normality that we all crave.”
Ms Sturgeon said it was a “difficult and frustrating” development but “while this setback is not easy, it is worth remembering that we are living under far fewer restrictions now than was the case a few weeks ago”.
She added: “The current situation is not what any of us want – but equally it is not lockdown. And vaccination is – with every day – helping us change the game.”
Level 0 is described as “near normal” but a number of restrictions still exist, including limits on the number of people individuals can meet socially in groups, and people are still advised to work from home where possible.
Earlier, government figures indicated Scotland has recorded two coronavirus deaths and 974 new cases in the past 24 hours.
The daily positivity rate was 5 per cent, down from 5.2 per cent the previous day, according to figures published on Tuesday.
There were 137 people in hospital on Monday with recently confirmed Covid-19, up from 128 on Sunday.
Seventeen people were in intensive care, no change on the day before.
The Scottish government’s announcement follows confirmation on Monday by Boris Johnson that England would see a four-week delay to Covid rules easing, buying more time for people to receive vaccinations.
Additional reporting by PA