A petrol bomb has been thrown at a mosque in Newtownards, County Down, in what police are treating as a racially-motivated hate crime.
The device, thrown at 01:00 BST on Friday, failed to ignite but racist graffiti was daubed on the building on Greenwell Street.
Cars were also set alight in Tavanagh Street and Sandhurst Gardens in Belfast.
All the incidents are being as racially-motivated hate crimes.
They follow a week of sporadic disorder which saw rioters attack police at various sites in Belfast and several members of the public reported they had been assaulted.
A total of five further arrests were made on Friday, bringing the total number of people arrested to 31.
On Friday night, the rear door of a restaurant on Ormeau Road was also kicked and racial slurs shouted to the workers inside.
Dozens of arrests
A 22-year-old man arrested following Friday’s protests in Belfast has since been charged with offences including disorderly behaviour and criminal damage. He is due to appear in court next month.
Two 14-year-old boys have been charged in Londonderry.
This comes after number of petrol bombs were found by police in the vicinity of Spencer Road in Derry.
A 37-year-old man was arrested in Portrush on suspicion of “intentionally encouraging riot” in relation to online activity.
“We continue to investigate all reports made to us in relation to the recent disorder on our streets and we will be making further arrests,” Ass Ch Con Melanie Jones said.
“The outpouring of support from our communities for their Muslim neighbours has been heartening and more accurately reflects the views of most of the citizens of Northern Ireland.”
Police said they would continue to have a visible policing operation in place across Northern Ireland this weekend.
Other incidents
In anticipation of the possibility of further disorder this weekend, the Police Service of Northern Ireland (PSNI) cancelled leave and asked officers to work on rest days.
The PSNI is also receiving support from Police Scotland which is to send 120 officers to Belfast to help quell the threat of violence.