Leader of the Alliance Party Naomi Long has described an attack on the party’s headquarters as "sinister".
Ms Long said she and her party would not be deterred from their work after graffiti was daubed on the building.
Police have said they are treating an attack on the office in Newtownabbey as a sectarian hate crime.
It was reported yesterday morning that graffiti had been sprayed on to external window and door shutters of the Farmley Road building in Glengormley and also a fence.
The PSNI said the attack could have occurred in the days prior to the report being made.
Chief Superintendent Stephen Murray said: "We have launched a proactive criminal investigation.
"The Police Service of Northern Ireland remains committed to doing everything we can to ensure our elected representatives and their staff can undertake their work free from harassment, intimidation or any other form of criminality.
"As part of our inquiries, we are appealing to anyone with information or who may have CCTV, dashcam or other video footage to get in touch.
"The number to call is 101 quoting reference 453 05/06/25."
Ms Long, who is also Stormont's Justice Minister, said that "reckless acts of intimidation will never deter Alliance from working to deliver for the people of Northern Ireland".
She said: "Those responsible for this sinister attack on party headquarters were deliberately trying to incite fear and intimidation.
"But we will remind them that these reckless acts will never deter Alliance.
"The abhorrent incidents that we've seen in recent months directed at politicians and political parties have been utterly unacceptable and are a direct consequence of the harmful rhetoric being spread by individuals both in the chamber and on social media."
She added: "This serves as yet another reminder that everyone in public life must play their part in reducing the temperature of the current toxic rhetoric and demonisation.
"It has a real-life impact and isn't conducive to stability or people's safety.
"I would like to thank the police for their prompt and professional response, as well as their ongoing efforts to investigate the incident."
