Nicola Sturgeon has angrily rejected claims of a “cover-up” after an outbreak of coronavirus was linked to a Nike conference in Edinburgh at the end of February.

At her daily coronavirus briefing, the First Minister said concerns over patient confidentiality meant details of the event were not made public earlier.

A BBC Scotland Disclosure investigation revealed more than 70 Nike employees from around the world attended a conference at the Hilton Carlton Hotel in Edinburgh on February 26 and 27,

It is understood one visiting attendee passed on the virus, with investigations finding at least 25 people linked to the event contracted Covid-19, including eight in Scotland.

The first Scottish coronavirus case was confirmed in Tayside on March 1, though this was unrelated to the conference.

Mass gatherings were not banned until March 16 and lockdown measures introduced on March 23.

Edinburgh South MP Ian Murray said the BBC report showed there was “a cover-up following the February outbreak.”

Asked about this claim, Ms Sturgeon said all appropriate measures had been taken and the cases had been reported in the Scottish Government’s usual figures.

She said: “On the accusation of a cover-up, that is complete and utter nonsense.

“I don’t know where that accusation comes from but it sounds like highly politicised nonsense as well.”

Ms Sturgeon said Health Protection Scotland set up an incident management team when the virus transmission became clear and contact-tracing had been carried out.

She added: “I was satisfied then and I am satisfied now that all appropriate steps were taken.

“At the time I probed whether we should be putting more information into the public domain.

“The advice, which is advice I accepted, is that it was not appropriate.”

She added: “One of the reasons for that was patient confidentiality at a time when the number of cases remained as low as they were.

“To identify where any case contracted the virus could potentially have identified the patients concerned.”

A statement from the Scottish Government later said the case was confirmed on March 3 with ministers informed of the development that evening.

Health Secretary Jeane Freeman was asked about the Nike conference during a series of urgent questions at the Scottish Parliament later on Tuesday.

Lothians MSP Neil Findlay asked why it had taken “two months and a BBC documentary” for the outbreak to be made public.

She replied: “The strong clinical advice we received was not to say where the trigger case had come from because it would then be possible to identify individuals…”

Ms Freeman said the first case connected to the conference was on March 4, triggering a contact-tracing exercise by Health Protection Scotland and international partners.

She told Daniel Johnston MSP: “I don’t believe that the Scottish Government could at any point in this entire exercise around Covid-19… be accused of secrecy.”

Meanwhile, the First Minister used the briefing to announce a £50 million fund to help the social care sector, which she said is “under immense pressure” as a result of Covid-19.

She said 1,912 patients have now died in Scotland after testing positive for coronavirus, up 50 from 1,862 on Monday.

The most recent figures for deaths in Scotland’s care homes, published by the National Records of Scotland on Wednesday May 6, show 43% of all Covid-19 linked registered deaths to date are in these settings.

As of Sunday, 65% of Scotland’s care homes have alerted the Care Inspectorate to at least one suspected coronavirus case since the start of the outbreak.

On that date, 44% of care homes in Scotland had a current suspected case.

Ms Sturgeon said the Scottish Government is “working hard to support the sector in every way we can”, with increased testing in care homes and supplies of personal protective equipment.

She said 13,763 people in Scotland have now tested positive for the virus, a rise of 136 from 13,627 Monday.

As of Monday night, 1,618 patients were in hospital with confirmed or suspected Covid-19, up 165 from 1,453 the previous day.

Of these, 81 are in intensive care, a rise of one.

The First Minister stressed the rise in cases is through patients suspected to have the virus, with confirmed cases down 14 in 24 hours to 1,131.

The rise in suspected cases in hospitals is being looked into, Ms Sturgeon added, as she cautioned against any “undue concern”.

She also announced £31 million to extend the small business grants scheme to those properties eligible for charitable or sports rate relief.

She again stressed lockdown restrictions – which were brought in seven weeks ago – remain in place for Scotland.

While the UK Government has published guidance for businesses ahead of a possible return to work, Ms Sturgeon said that was “not yet operational in Scotland since at this stage we are not currently encouraging more people to go back to work”.

She said the Scottish Government is working with employers and trade unions to develop its own guidance on safe workplaces.

Working groups have been set up for 14 different sectors of the economy “to consider how quickly and in what manner we can start to return to work”.

Here she said “early priorities” will be the retail, manufacturing and construction sectors, adding industries such as tourism, energy, finance and food and drink are also being considered.

Later on Tuesday the UK Government’s Scotland Office minister Douglas Ross apologised for governments’ role in delaying the lockdown.

He told BBC’s Drivetime with John Beattie: “I think every government will look back at their actions and see where mistakes have been made, and 2,000 lives lost in Scotland because we didn’t lock down soon enough will be replicated in other parts of the United Kingdom and in other parts of the world.

“And that’s 2,000 lives that have been lost, families that have been left distraught, and I apologise to everyone who has been let down in any way by the respective governments.

“We can look back with hindsight and say we could have done this differently, we could have done that differently, but we also have to look forward to see how we get out of this, and make the best decisions going forward in the full knowledge that we will have to look back at some point, and see what was right, what was wrong.

“But 2,000 lives as a result of not locking down earlier is something no one can support.

“This was a Scottish Government decision, likewise there were UK Government decisions, there will be mistakes made by every government in every country across the world.

“We are all dealing with a virus that wasn’t known about 150 days ago.”