Six people have tested positive for coronavirus in an outbreak at an NHS England test and trace call centre in North Lanarkshire.
Sitel, which carries out contact tracing for the NHS, said it was aware of a “local outbreak” at its Motherwell site.
Deputy first minister John Swinney told BBC Radio’s Good Morning Scotland the alarm was raised at 08:00 on Sunday.
He said “extensive contact tracing” is now under way.
On Sunday NHS Lanarkshire said it was aware of a number of “potentially linked cases”.
Sitel said it was “urgently investigating” the outbreak with Public Health Scotland.
The company said it had requested that all staff who have been working at the site undergo testing within the next 24 hours. “We take the safety and wellbeing of our staff very seriously,” it said in a statement.
Dr David Cromie, NHS Lanarkshire consultant in public health medicine, said on Sunday: “We became aware… of a number of potentially linked cases of coronavirus (Covid-19) in Lanarkshire.
“We instigated some immediate measures to reduce risk and are currently investigating the situation.”
Earlier, the Scottish government said 23 new cases of Covid-19 had been detected across Scotland in the past 24 hours, although only three of these were in the Lanarkshire health board area.
First Minister Nicola Sturgeon said it was still a low number of cases and fluctuation was “to be expected”.
The proportion of positive tests remains well below 1%.
It follows an increase of 21 new cases on Saturday, which was the highest daily figure in almost a month.
Health officials said at the time they did not believe they were dealing with a linked cluster as the new cases were spread over a large area of Scotland.
The Scottish government said contact tracing is under way following the detection of “a small number of potentially linked cases in North Lanarkshire”.
“Where potential clusters of cases develop we must find them and act quickly to prevent further spread and we are grateful to local partners for their swift response,” a spokesman said.
The spokesman said “a small increase in the number of cases is not unexpected as lockdown is lifted”, adding that it highlights the importance of the public co-operating with contact tracers as well as following guidelines on social distancing and wearing face coverings.