Nicola Sturgeon is preparing to outline new coronavirus restrictions at Holyrood.
The first minister, along with her counterparts in Wales and Northern Ireland, is due to take part in a Cobra meeting with Boris Johnson.
She will then meet her cabinet before addressing the Scottish Parliament in the afternoon.
It comes after the UK’s chief medical officers raised the coronavirus alert to Level 4.
This means transmission of the virus is “high or rising exponentially”.
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Downing Street confirmed on Monday night that Mr Johnson had spoken on the phone to the first ministers of Scotland, Wales and Northern Ireland, and that they had all agreed to act “with a united approach, as much as possible, in the days and weeks ahead.”
Nicola Sturgeon tweeted that her Holyrood statement would go ahead.
At her daily briefing on Monday, she said additional lockdown restrictions would “almost certainly” be put in place in Scotland in the next 48 hours.
She said coronavirus was spreading in the country again and “further and urgent action” was needed to stop the increase warning that, if left unchecked, it would lead to more cases, people in hospital and deaths.
She said the Scottish government was prepared to introduce “a package of additional measures” but would aim to avoid a full-scale lockdown such as the one imposed in March.
On Monday, the number of cases in Scotland rose by 255, representing 6.3% of those newly tested, up from 5.4% on Sunday.
Ms Sturgeon said the Scottish government endorsed the warning of UK chief scientific adviser Sir Patrick Vallance that new cases could rise daily by 50,000 by October.
“In my view, further and urgent action will now be needed to stop the increase in the number of cases,” she said.
She added: “At the heart of this decision is a simple truth, the longer we wait to introduce new measures, the longer these measures are likely to be in place.
“If we move sharply now to get the virus back under control, we can minimise the time we all spend under any new restrictions.
“If we wait it will take longer, potentially a lot longer, to come out of the other side.”
In Northern Ireland, indoor household mixing is no longer permitted. Similar measures could be seen here nationally, and the first minister has warned that hospitality could also be affected.