Police are investigating the placing of an Irish flag and a picture of Taoiseach Leo Varadkar on a loyalist bonfire in Co Tyrone as a "hate crime".
The towering pyre in Moygashel, themed as an anti-Northern Ireland Protocol bonfire, attracted attention online after a boat was placed on the top of it.
By Saturday evening, an Irish tricolour and a republican flag, as well as a picture of Mr Varadkar, had been added on the boat.
Read more: Loyalist bonfire with boat on top lit in Co Tyrone
The PSNI has confirmed it is investigating the incident.
Chief Inspector John Keers said: "We received a report on Saturday evening, July 8, in relation to material placed on a bonfire in the Main Road area of Moygashel. Police are treating this as a hate crime."
On the side of the boat a banner reading "Good Friday Agreement? That ship has sailed" was hung, with a mock copy of the 1998 accord across which the words "null and void" were printed.
Given the title No Irish Sea Border Bonfire, in reference to opposition in unionist and loyalist communities to post-Brexit trading arrangements, the bonfire was lit at around 11pm after a parade and an address by loyalist activist Jamie Bryson.
Unionist leaders have condemned the placing of the Irish flag and Mr Varadkar's picture on the bonfire.
DUP leader Sir Jeffrey Donaldson tweeted: "I am proud of my tradition but if we want respect for our culture & identity, then we must show respect to others.
"Burning the flag of our neighbouring state & a poster of the head of government of that state is disrespectful and wrong. It is not culture!"
Ulster Unionist leader Doug Beattie said: "This is not acceptable, it is childish and promotes hate. Again the many are let down by a few."
Most of the bonfires to mark Northern Ireland's traditional July 12 celebrations will be lit on July 11.
The Twelfth marks the victory of Protestant King William of Orange over Catholic King James II in the Battle of the Boyne in 1690, an act that secured a Protestant line of succession for the British crown.
There has been controversy around bonfires in previous years, with election posters and Irish flags hung from the stacks of wood, with some towering more than 100ft high.
Meanwhile, the annual Drumcree parade is taking place in Co Armagh on Sunday, from Carleton Street Orange Hall in Portadown to a church service at Drumcree Parish Church.
It is 25 years since the parade was first prevented from completing its traditional return route along Garvaghy Road, with the Parades Commission again refusing permission for the return leg this year.
The stand-off at Drumcree made headlines in the 1990s with nationalist residents of the Garvaghy Road resolutely opposed to the parade passing through the area, leading to violent clashes for several summers and political tensions necessitating a major security operation.
DUP MP Carla Lockhart said it was a "very sad day that 25 years on from this dispute we're still in the same situation where Orange feet are not welcome on a particular stretch of road".
She told the BBC's Sunday Politics programme: "I want to see a society where our culture is respected, our identity is respected, and I think it is no big thing to ask that the Garvaghy Road Residents Association enter into some form of mediation.
"Unfortunately for many, many years their intransigence has actually been rewarded by the Parades Commission.
"We can't move on if there is no respect or tolerance for a 10-minute walk down a route which has changed enormously over the last 25 years."
Most of the hundreds of bonfires constructed in loyalist neighbourhoods across Northern Ireland pass off without incident, but several continue to be the source of controversy.
In previous years, there have been complaints from nationalist and cross-community politicians about their images being placed on the fires.
It is the busiest date for the Northern Ireland Fire and Rescue Service which usually deals with hundreds of calls related to the towering pyres.
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