Police are being given fresh powers to break up large house parties and councils will be able to shut down firms that fail to comply with coronavirus regulations under new measures announced by Nicola Sturgeon.

The First Minister announced the changes as the number of new cases of Covid-19 in Scotland reached the highest level for almost three months.

Seventy-seven people tested positive in the last 24 hours, taking the total number of cases recorded in Scotland to 19,534.

Ms Sturgeon said the number of new cases highlights the “need for continued caution”, and said it is clear Scotland cannot yet move into phase four of the four-step route map out of lockdown.

To help tackle the spread of the virus, she announced plans to give both Police Scotland and councils more powers.

Ms Sturgeon said: “The Scottish Government has powers under emergency legislation to issue directions in respect of a class of premises – for example, to close all pubs in a particular postcode.

“We intend to give local authorities the power to act in respect of individual, specific premises that are breaching guidelines and risking transmission of the virus.”

This power would enable local authorities to close premises or to impose conditions on their opening.

Police will also be given powers to break up house parties as they “pose a very real and significant risk of clusters and outbreaks”, the First Minister added.

She said: “For use in cases of flagrant breach and as a last resort, we intend to give the police powers of enforcement to break up and disperse large indoor gatherings.”

These new powers, which will come into force from Friday August 28, are “necessary to continue to suppress the virus”, she insisted.

In the latest review of lockdown restrictions outlined at Holyrood on Thursday, the First Minister was able to confirm a number reopenings can go ahead under phase three.

She has brought forward the reopening date for gyms and swimming pool from mid-September to August 31, but said she cannot yet give a date for when workers can return to non-essential offices.

The reopening of offices and call centres not deemed essential would “significantly increase the risk of indoor transmission” of the virus, she said, and “make it more difficult to keep schools open”.

She added: “This does come down to difficult judgments about priorities.

“We have made clear that our priority is to enable children to be safely back at school. And with the virus at its current levels, that means we cannot do everything else we would like to do – like bring back non-essential offices.”

She confirmed that from August 24, some outdoor live events can take place, organised outdoor contact sports will resume for people of all ages, and driving lessons can return.

Giving indicative dates for future reopenings, the First Minister said that from September 14 “sports stadia will be able to reopen, though only for limited numbers of spectators and with strict physical distancing in place”.

Some safety pilots of professional sports events may take place before then, she added.

Indoor contact sports activities, entertainment and cultural sites – such as theatres and live music venues – can reopen from September 14, and wedding and civil partnership receptions and funeral wakes can have more attendees, although numbers will remain restricted.