The First Minister said Scotland recorded 10 coronavirus-linked deaths and 4,323 cases in the past 24 hours.
Speaking at a Scottish Government coronavirus briefing in Edinburgh she said the daily case figure is “the largest we have ever recorded in a single day” but highlighted more testing now takes place than in the early stages of the pandemic.
Ms Sturgeon said new cases in Scotland have more than doubled in the past week, making this “one of the sharpest rises we have experienced at any point during the pandemic”.
Hospital and intensive care cases have also increased in the past 24 hours.
She warned Scotland is now at a “fragile and potentially pivotal moment” in the fight against the virus as vaccinations have weakened the link between cases and serious harm but not completely broken it.
She added: “That means the rise in cases in the last week may well result in more people having to go to hospital in the coming days, perhaps requiring intensive care treatment, and, unfortunately, a rise in cases like this will still lead to an increase in numbers of people dying.
“That also means that, if this surge continues, and if it accelerates, and if we start to see evidence of a substantial increase in serious illness as a result, we cannot completely rule out having to reimpose some restrictions.
“Of course, we hope not to have to do that and, if we did, we would be as limited and as proportionate as possible.
“However, as has been the case throughout so far, and up until this point, what happens in the next few weeks will depend, to a large extent, on all of us.”The First Minister added: “We always knew cases were likely to rise as restrictions eased, so to some extent what we are seeing now is not entirely unexpected.
“That said the scale of the increase is still a cause of real concern.”
She urged people to adhere to the remaining restrictions, such as wearing face coverings in indoor public areas, as well as regularly taking lateral flow tests and getting fully vaccinated if they have not already.
With vaccination “making a big difference”, Ms Sturgeon said many of the new cases were in younger people, who are “less likely” to have had both doses of vaccine.
She said that “around half of all new cases right now” were in people under the age of 25.
So far, 4,850,552 people have received the first dose of a Covid-19 vaccination and 3,587,145 have had their second.
Giving a further update on the daily figures, she said the death toll under the daily measure, of people who first tested positive for the virus within the previous 28 days, is now 8,080.
The daily test positivity rate is 14.5%, up from 12.4% the previous day.
A total of 364 people were in hospital on Monday with recently confirmed Covid-19, up by eight on the previous day, with 43 patients in intensive care, up two.