Nicola Sturgeon is preparing to outline new restrictions designed to limit the spread of coronavirus in Scotland.
She will address Holyrood on Tuesday afternoon following a Cobra meeting with Prime Minister Boris Johnson.
Her counterparts in Wales and Northern Ireland will also take part in the meeting in a bid to take “a united approach” as far as possible.
It comes as the UK’s Covid-19 alert level moved to 4, meaning the virus is “high or rising exponentially”.
Downing Street confirmed on Monday night that Mr Johnson had spoken on the phone to the first ministers of Scotland, Wales and Northern Ireland.
They had all agreed to act “with a united approach, as much as possible, in the days and weeks ahead.”
In England, restrictions will include a 22:00 closing time for pubs, bars and restaurants from Thursday.
And in an extension of Covid curbs in Northern Ireland, households will not be able to meet indoors from 18:00 on Tuesday.
The prime minister will outline the measures in the Commons on Tuesday afternoon before addressing the nation in a live broadcast at 20:00.
In a post on Twitter, Nicola Sturgeon said she would agree any new restrictions with her cabinet before making a statement to the Scottish Parliament.
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.”