There is “no place for racism in Northern Ireland”, Michelle O’Neill has said.
Executive ministers met earlier at Stormont Castle to discuss recent scenes of violent disorder on the streets of Belfast.
The Northern Ireland Assembly has been recalled with MLAs returning from summer recess to take part in a special sitting at noon.
Outside Parliament Buildings, the Irish Congress of Trade Unions led a rally in opposition to the rioting seen in the capital on Saturday, Monday and Tuesday evenings following anti-immigration protests.
Police and members of the public have been attacked and two businesses owned by people from a minority ethnic background have been destroyed in south Belfast. There have also been incidents in north and west Belfast.
There was further disorder on Wednesday night, with police coming under attack in east Belfast.
Police said five arrests were made after bins were set alight blocking Connswater Street, and officers came under attack. One police officer was injured.
There have been 17 arrests in total.
The Police Service of Northern Ireland said it has asked for support, submitting a request to National Police Co-ordination Centre for additional officers from across the United Kingdom to support the policing operation.
Assistant Chief Constable Melanie Jones said the Mutual Aid officers will provide vital resilience and support and will be given all of the necessary equipment and familiarisation training.
It comes amid widespread disorder across the UK which appears to have been sparked by misinformation spread online following the fatal stabbing of three girls in Southport.
Earlier this week, Ms Jones said a paramilitary element is suspected of co-ordinating violence in Belfast.
On Monday, four men linked to disorder on Saturday appeared at Belfast Magistrates’ Court, while a 15-year-old boy appeared before the same court on Wednesday charged with rioting.
All were remanded.
Following the Executive meeting, Ms O’Neill, deputy First Minister Emma Little-Pengelly, and Chief Constable Jon Boutcher, stood shoulder to shoulder to speak to media.
Ms O’Neill said ministers are “unequivocally collective in our determination to say no to racism, and stand firmly united in terms of what we see unfolding in front of us”.
“There is no place in our society for racism in any of its forms,” she said.
“The racist attacks on people, on businesses and homes are absolutely wrong, and have created such a deep fear. A fear that I think perhaps none of us have ever seen before among many parts of our community.
“There are many people feeling extremely vulnerable, feeling fearful, fearful for their families.
“We have mothers who are afraid to walk their children to the park, we have children who are afraid to go to youth clubs and to schemes. We have healthcare workers that are afraid to go to work. We have nurses that are afraid to go home and that is not acceptable.
“That is the real, human impact of this type of activity, this type of racist activity in our society. It speaks volumes in terms of hate because that is what it is and it must stop.
“Those responsible must and will face the full rigours of the force of the law.”
On Wednesday, Secretary of State Hilary Benn condemned “racist violence” in Belfast in recent days and stressed that it “does not represent Northern Ireland”.
He said it should be a cause of shame that some people currently do not feel safe in their own homes, and urged those behind the disorder to stop.
MLAs debated a motion condemning “criminal damage and targeting of businesses in recent days”.
The motion also calls on Ms O’Neill and Ms Little-Pengelly to finalise the draft refugee integration strategy and associated delivery plan, to bring forward the renewed Race Relations Order, and set out the process of replacing the racial equality strategy 2015-25 by the end of 2024.
