The office of the Ulster Unionist Party leader has been targeted overnight, it's emerged.
Windows at Doug Beattie's constituency office, on Bridge Street in Portadown, were smashed during the attack.
A spokesperson for the Ulster Unionist Party told Belfast Live that the damage was discovered on Monday morning.
Read more: Election 'most important in a generation' DUP leader tells anti-protocol rally
Police are appealing for information following the report of criminal damage.
Sergeant Berry said: “It was reported that sometime between 8.30pm yesterday (Sunday 27th March) and 8.30am today, Monday, a concrete block was thrown at the main window of a property at Bridge Street in the town.
“Enquiries are at an early stage, and I appealing to anyone who may have witnessed any suspicious activity, or have any information which could assist, to contact police on 101, and quote reference number 675 of 28/03/22.
"Information can also be provided to Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org."
Condemning the incident, SDLP's Nichola Mallon said: "Disgraceful attack on Doug Beattie and his staff. This achieves nothing and should be universally condemned."
Reacting to photographs of the damage shared online, Jamie Bryson said: "This is to be condemned. The way to show opposition to the UUP is simply be rejecting them at the polls.
"We need to engage with Doug Beattie in public debate and outline the view of why the UUP are so wrong and damaging the Union.
"Attacking his premises doesn’t advance the issue."
The Ulster Unionist Party leader has accused unionist and loyalist organisers of anti-Northern Ireland Protocol rallies of stoking tension in the region.
In a lengthy statement on Sunday, Doug Beattie said that his party will not be involved in rallies that he said were “raising tensions” in Northern Ireland.
DUP leader Sir Jeffrey Donaldson was among those who addressed a rally against the protocol on Friday, alongside TUV leader Jim Allister, Baroness Hoey, Ben Habib and Jamie Bryson in Ballymoney, Co Antrim.
It was the latest in a string of protests against the post-Brexit arrangements for Northern Ireland, which are fiercely opposed by unionists and loyalists.
Read more: Stormont Minister updates policy on wearing masks in schools
Read more: Euro 2028: Northern Ireland remain part of bid despite Stormont warning
To get the latest breaking news straight to your inbox, sign up to our free newsletter.
