Mass gatherings in Scotland could be off for up to four months due to the coronavirus pandemic.
As guidance for events involving more than 500 people came into force across the country the first minister said it could last until the summer.
Nicola Sturgeon also warned Scotland faced an "unprecedented situation" and a "very challenging" few months.
Later the prime minister said everyone should now avoid "non-essential" travel and contact with others.
Boris Johnson also said people should work from home and avoid pubs, club, theatres where possible, as part of a range of stringent new measures.
And he told the media anyone in the same house as someone who has a cough or fever will also have to isolate for 14 days
Latest figures showed a total of 171 confirmed cases of Covid-19 in Scotland, and one fatality.
At a media briefing in Edinburgh on Monday morning it emerged the situation in relation to school closures could be different across the country.
Health Secretary Jeane Freeman also updated the media on what action was being taken across Scotland, including;
- Extra ICU ventilators have been ordered, which will take the total to 700
- the GP surveillance testing system, used to monitor seasonal flu outbreaks, will be expanded from 42 to 200 GP practices and cover 1.2m people.
- it will now be used to test those with relevant symptoms in a bid to pick up virus hotspots and monitor how Covid-19 is spreading across the country
- councils may be asked to redeploy staff to address shortages in care homes.
Scotland's Chief Medical Officer Dr Catherine Calderwood said that if the virus becomes a seasonal virus, she would hope there would be a vaccine in place by this time next year.
On Sunday UK Health Secretary Matt Hancock said they will be asked to stay at home for a very long time.
But on Monday Transport Secretary Grant Shapps said people over the age of 70 would be asked to self-isolate "as and when the moment is right" - but that they would still be able to go outside and "walk the dog".
Scotland's national clinical director said older people across the UK would not be asked to stay at home.
Speaking on the BBC Radio Scotland's Good Morning Scotland programme, Prof Jason Leitch addressed concerns about the apparent variation in advice.
Prof Leitch said over-70s would not be asked to stay at home but rather to reduce their social contact, for example by not going to a pub, bingo or church.
He added: "In fact, quite the opposite, we expect family contact to increase in that group so that those people will be looked after. The last thing that we want is four months of loneliness."
On Sunday it emerged six residents at a care home in North Lanarkshire had tested positive for coronavirus.
During the briefing on Monday Ms Sturgeon said the Scottish government's driving priority would be saving lives and protecting the public.
She also confirmed daily briefings will be given to media to provide information and advice on tackling the pandemic.
While health is devolved the first minister added that she expects there to be a high degree of commonality in decision-making across the UK as it is based on the same scientific advice.
The Scottish Courts and Tribunals Service has reiterated its call for anyone attending a case or a hearing to stringently follow the current medical advice.
It was announced last week that as part of coronavirus planning, events involving more than 500 people should not go ahead from Monday.
Official guidance was published on Sunday for organisers, sports governing bodies, supporters and clubs.
The government does not have the power to cancel events, but has called on organisers "to act responsibly".
On Monday organisers of the Edinburgh Marathon confirmed the race, scheduled for 24 May, will now be held on 6 September.
And the 2020 edition of the Etape Caledonia cycling event, due to take place on 17 May, has been postponed.
Capital Theatres announced it will be immediately cancelling or postponing all performances at the Festival Theatre, The King's Theatre and The Studio in Edinburgh throughout March and April as an initial measure. Customers who have tickets for events will automatically receive a full refund.
Concerts, including Radio 1's Big Weekend in Dundee, have been cancelled while shows and major exhibitions have also been scrapped.
On Friday it was announced the Scottish football season has been postponed until further notice due to the virus.
Other events hit include Scotland's Six Nations match against Wales in Cardiff.
But horseracing is set to continue behind closed doors until the end of March and a meeting is being held at Kelso in the Borders on Monday afternoon.
Large gathering ban - what the government says
- Mass events should not take place from Monday 16 March 2020
- The definition of a mass event is any event expected to involve more than 500 attendees
- The advice applies to all sectors including sporting events, cultural events, and religious gatherings
- Sports may also wish to consider the viability of holding grassroots and club activity, in light of increased spread of the virus
- Sports should consider cancelling sessions specifically aimed at older adults given the increased risk posed to those individuals
- Further measures may be taken as the situation develops