The King’s coronation celebration in Edinburgh saw several protests across the city and two arrests confirmed by police.
Police Scotland said on Twitter that two women, aged 20 and 21, were arrested in connection with an alleged breach of the peace after they reportedly attempted to climb over crowd barriers.
The force is yet to confirm other arrests.
This Is Rigged tweeted that two of its campaigners were arrested by police, and Republic, a campaign to abolish the monarchy, said it was “concerned” to hear about arrests.
Republic tweeted: “Very concerned by the arrest of three peaceful protesters at the end of a successful day. Currently talking to police to find out more and get them released.”
Protesters were asked to stand in designated areas outside the High Court on the Royal Mile and outside of the Scottish Parliament.
Scottish Government minister and Scottish Greens co-leader Patrick Harvie addressed around 100 protesters from the Our Republic campaign, outside Holyrood.
He told the PA news agency: “Republic and Our Republic have struck the right balance by continuing to make the case for the change they seek: an elected head of state.
“In the meantime, talk about some of the smaller issues that should be addressed for as long as the monarchy last, like, for example, some of the tax loopholes they have that others don’t.”
He said the service of thanksgiving taking place at St Giles’ Cathedral was a “Game Of Thrones-style cosplay exercise” and hit out at the disruption in Edinburgh this week.
Mr Harvie said he had to take a 25-minute detour from St Andrew’s House to the Scottish Parliament on Wednesday.
He said: “I recognise there is going to be disruption when there is a major event on.
“But let’s think about how a modern, democratic head of state would go about their business in Scotland.
“It wouldn’t have this level of pomp and ceremony and rigmarole.”
A member of the Republic campaign earlier told PA that the monarchy is a “symbol of the state that this country is in”.
“There is also the democratic deficit. He (Charles) has got a very important, very powerful position in this country because his mother died.
“He has never been voted into office, we don’t have the chance to get rid of him.
“It’s old fashioned, it’s antique and it’s high time we got rid of it.”
Scottish Secretary Alister Jack said: “It’s absolutely right that people should have the right to protest, that’s democracy.
“As regards to the Scottish Greens, my dealings with them so far is that every position they’ve taken has been the wrong position.
“If that’s the position they’ve taken today then I think the monarchy is safe for generations.”