NICOLA Sturgeon has tightened coronavirus rules to restrict gatherings to a maximum of six people in Scotland amid concerns the pandemic is "accelerating".

The First Minister said the change will apply in all locations, including homes, bars, restaurants, gardens and parks.

It comes after similar measures were introduced in England.

A maximum of six people from two households will now be allowed to meet up, with limited exceptions for organised sport, worship, weddings, civil partnerships and funerals.

Children under 12 are not counted within the limit.

The new rule comes into force from Monday, although Ms Sturgeon asked Scots to start abiding by it immediately.

It marks a stark change from the previous position, where groups of up to eight people from three households were allowed to meet indoors, and up to 15 from five households were allowed to meet outdoors.

Elsewhere, the reopening of stadiums, music venues and theatres has been paused due to the recent rise in cases. They were due to reopen next week but this has been pushed back to October 5.

Business leaders expressed disappointment at the situation and called for clear guidance for those sectors waiting to reopen.

The restrictions came as more than 430,000 Scots downloaded the new Protect Scotland contact tracing app in its first day of operation.

The smartphone app can alert users if they have been in close contact with someone who has tested positive for Covid-19 and advises them to self-isolate and get tested.

Speaking in Holyrood, the First Minister said that when lockdown measures were reviewed six weeks ago, Scotland had recorded an average of just 14 new cases a day over the previous week.

Three weeks ago, this had risen to 52 new cases a day. But in the seven days up to Wednesday, the average daily rate was 155.

The R number - the average number of people infected by each person with coronavirus - is now possibly as high as 1.5.

Ms Sturgeon said: "Over the past week, we have also had to impose additional restrictions on people living in five local authority areas in Greater Glasgow and Clyde – Glasgow City, East and West Dunbartonshire, Renfrewshire and East Renfrewshire.

"So rather than the threat to public health receding, the pandemic is at this stage accelerating again – albeit, and thankfully, from a low base and not as rapidly as it was back in March and April."

The resumption of indoor contact sports and certain outdoor and indoor live events, as well as indoor soft play, has also been pushed back to October 5.

While fans will not be able to return to stadiums until at least that date, Ms Sturgeon said two pilot football matches due to take place this weekend will proceed as planned.

She said working from home should remain the default position, with a further review around the reopening of offices and call centres due on October 1.

No date has been given for the return of nightclubs or standing indoor concerts.

Face coverings will now be mandatory in indoor hospitality venues for staff and customers when not eating and drinking.

Dr Liz Cameron, chief executive of the Scottish Chambers of Commerce said: “It is disappointing that we seem to have taken a step back in terms of compliance with guidelines while the virus has taken steps forward.

"We need to control the spread of the virus more effectively and we urge all to follow the rules. We can ill afford a return to stricter measures."

She added: "For the sake of our theatres, live music venues, soft play and indoor contact sports facilities, clear guidance on when they can reopen safely is also required quickly."

Fiona Campbell, chief executive of the Association of Scotland’s Self-Caterers (ASSC), said the new restrictions were a “particularly worrying development for Scotland’s £723m self-catering sector".

She said: "These changes were announced at relatively short notice, and will come into effect this Monday, and will have a significant impact on businesses in terms of bookings in self-catering properties."

Ms Sturgeon said Scotland is not likely to enter the fourth and final phase out of lockdown "for some time yet".

She said there were 161 new coronavirus cases in the last 24 hours, with 65 of these in the Greater Glasgow and Clyde area, 46 in Lanarkshire, 12 in Lothian and eight in Ayrshire and Arran.

The remaining 30 were spread across eight different health board areas. No confirmed Covid deaths were registered.

Residents in Glasgow City, East and West Dunbartonshire, Renfrewshire and East Renfrewshire are still asked not to visit other households.

Ms Sturgeon said approximately 96 per cent of businesses in Scotland are now trading again.

She said: "People are meeting up more, going out more, and travelling more. All of that is positive.

"But as we released ourselves from lockdown, we also released the virus. We gave it more opportunities to spread and so it was always likely that we would see a rise in cases."

The First Minister said the decision to delay further reopenings had not been taken lightly.

She said: "But right now, given the rise in cases, it’s the only responsible decision we can reach."

She added: "However, I want to be clear that while we still face a battle to get and keep Covid under control, we are in a stronger position than earlier in the year."

She said it is "vital to do everything we can to stop cases rising further before winter".

Ms Sturgeon said: "I know that making those choices – keeping our distance from friends, staying in small groups indoors, washing our hands regularly – gets harder and more tiresome as time passes.

"But they are more important now than they have been for months."

Elsewhere, she said the new voluntary smartphone app will "complement existing contact tracing methods" and could potentially help to avoid local lockdowns.

The app does not store details on an individual or their location but uses encrypted, anonymised codes exchanged between smartphones to determine close contacts with people who test positive.

A close contact is defined as someone who has been within two metres for at least 15 minutes.

If a person tests positive for coronavirus, they will be sent a unique code to their mobile and - with their permission - the app's data will then be sent to a server so close contacts also using the app can be notified by text and advised to self-isolate.

Designed by software developers NearForm for NHS Scotland, the app uses the same technology as the Irish and Northern Irish proximity tracing apps.

Its technical development is understood to have cost less than £300,000.

A recent study by Oxford University and Google found a well-staffed manual contact tracing workforce combined with 15% uptake of such a smartphone app could reduce infections by 15% and deaths by 11%.

Travellers arriving in Scotland from Hungary and La Réunion will be required to quarantine on arrival from 4am on Saturday. Sweden will be added to the list of countries exempt from the 14-day quarantine requirements.