Reports suggest bottles, bins and metal bars were used as weapons against police during several nights of unrest.
Petrol bombs were thrown in Carrickfergus just north of Belfast and cars were set alight in Londonderry this week.
Around 11 people have been arrested at several demonstrations across the country with children as young as 12 seen taking part in the protests.
A 13 and 14-year-old were arrested at a riot that involved roughly 600 people.
The protests are believed to be in response to issues surrounding the Northern Ireland Protocol and the government’s decision to not prosecute attendees at a high-status Republican funeral.
Last week Irish police decided not to prosecute 24 Sinn Fein politicians for attending a large funeral of former IRA member Bobby Storey despite strict COVID-19 rules limiting public gatherings.
Protesters have called for the resignation of PSNI Chief Constable Simon Byrne who oversaw the decision.
Northern Ireland First Minister Arlene Foster slammed the violence and said there was a “criminal” element behind the demonstrations who were whipping up disorder.
As part of the Protocol, Northern Ireland remains part of the EU Customs Union meaning goods entering from Great Britain are subject to additional checks.
This has meant some hauliers have been held up at ports as loyalists oppose an Irish Sea border.
Earlier this year, border staff were removed from ports in Belfast for their safety after alleged loyalist graffiti was seen in nearby towns calling staff “targets”.
The UK has been negotiating with the EU to arrange a replacement of the Northern Ireland Protocol as hauliers are kept waiting at ports.
In January, there were reports of Irish supermarkets running out of goods as trucks were severely delayed at ports for not having the right paperwork.
But EU Vice-President Maros Sefcovic denied Cabinet Minister Michael Gove’s request to extend the Northern Ireland grace period – which limits the checks on borders – by several years.
Loyalists fear the Protocol creates a border between the UK and Northern Ireland and have been demonstrating against it.