According to the Dagbladet newspaper, police believe between 12,000 and 15,000 were gathered in Eidsvoll Square outside the Norwegian parliament on Friday afternoon to show solidarity with those in the US protesting the death in police custody of George Floyd, as well as to protest racism and police brutality in Norway.
But while the scale of the protests underlined the importance of the issue, it also posed a health threat, deputy health director Espen Rostrup Nakstad told Norway's state broadcaster NRK.
“If you gather a lot of people in one place, the likelihood that one of them is ill without the person even knowing it is not negligible,” he said.
“Then we can get a superspreader situation, where you are close to each other, and one person infects a lot of people. Then we suddenly could have a small outbreak in Oslo, and we want to avoid that.”
He said it was important that all who attended the demonstration get tested if they experience any symptoms in the coming days.
A study by Ben Cowling at Hong Kong University recently estimated that 70 percent of the those infected with coronavirus did not pass on the disease, and that 20 per cent of Covid-19 patients are responsible for 80 percent of transmissions.
Most transmission now appears to take place at superspreader events, such as choir meetings, gym classes, business conferences, and also, potentially political demonstrations.
While the protest's organisers on Thursday night said they would try to ensure that the protest respected social distancing guidelines, with no single group of more than 50 meeting, many people on the Facebook page said before the event that they intended to break the guidelines.
In the end, thousands of protesters gathered in front of the Norway's Storting parliament, holdings signs saying “Black Lives Matter”, “We can't breathe”, or “No Racism on Our Streets.”
Many people dropped a knee, a symbol of honouring victims of police violence.
Police said that they would not enforce either the one-metre rule or the rule limiting gatherings to 50 people.
“The police and society at large value freedom of speech, so the police will not do anything against the fact that there is a larger crowd gathered here now,” police chief Svein Arild Jørundland told NRK.
At 3.30 in the afternoon, around 150 to 200 protesters gathered outside the US embassy on Oslo west, and an hour later the crowd had swelled into the thousands.
You can see a live stream of the event below: