Organisers of anti-racism protests in Northern Ireland will be reported to be Public Prosecution Service, police have said.
Black Lives Matter demonstrations took place in cities across the island of Ireland on Saturday afternoon.
Some of the biggest crowds gathered at Custom House Square in Belfast and outside the US Embassy in Dublin.
In Northern Ireland, Assistant Chief Constable Alan Todd had urged organisers to call off the rallies sparked by the death of George Floyd in police custody in the US.
The Police Service of Northern Ireland conducted checks on roads and at transport hubs ahead of the protests.
As people arrived, many wearing face coverings and gloves, at the demonstration in Belfast they were handed flyers by police officers detailing social-distancing rules. Some were issued with community resolution notices.
Organisers had marked out social-distancing measurements and encouraged those attending to space out.
They heard speeches and at one stage knelt on one knee in solidarity.
ACC Todd later issued a statement in which he said police estimate numbers of around 500 at the demonstrations in Belfast and Londonderry.
He said although a planned protest in Newry had been cancelled, a “small crowd did gather but dispersed quickly on our request”.
The senior officer confirmed community resolution notices had been handed out, and revealed protest organisers will be reported to the Public Prosecution Service (PPS).
“We estimate there were less than 500 people in attendance at each event and a significant number of Community Resolution Notices (CRNS) and fines were issued in both Belfast and Derry/Londonderry,” he said.
“A number of individuals, including organisers, will now be reported to the Public Prosecution Service with a view to prosecution. We will also conduct follow up enquiries to seek to identify others who may have committed offences.
“The Health Protection Regulations are in place to protect us all during this pandemic and it is everyone’s responsibility to adhere to them to protect our society.”
In Dublin, there were also calls for social distancing to be observed as crowds protested outside the US Embassy.
Marks were made on the road to show people how far apart to stand.
However, protesters appeared closer together as more numbers arrived, many holding placards which carried messages of support for the Black Lives Matter campaign.
Gardai say investigations are ongoing after thousands of people took part in a similar rally in Dublin last Monday.
The Irish police force said officers have been in contact with protest organisers to make them aware of their obligations under Covid-19 regulations, warning that demonstrations may constitute a potential breach of the regulations.