Police estimate 3,000 people have taken part in a loyalist protest in west Belfast.
Police said the “un-notified procession” left Woodvale Park at about 19:10 BST and made its way to Shankill Leisure Centre.
They said an evidence-gathering operation was in place.
“Organisers of parades/processions are required to give formal notification of their intentions which was regrettably not provided,” Ch Insp Darren Fox said.
“The numbers were also in excess of that permitted under the public health regulations.
“Police issued a number of warnings and we will now review all the footage gathered and consider any suspected breaches of the Public Processions (NI) Act 1998 and offences in respect of the Health Protection (Coronavirus, Restrictions) Regulations NI 2021.”
The event had been organised in opposition to the Northern Ireland Protocol.