Belfast City Council is investigating after a portrait of a former lord mayor was damaged.

The painting of Democratic Unionist Party (DUP) peer Lord Browne was on display at Belfast City Hall.

It was removed from a wall and the glass in its frame was “smashed”, a DUP councillor said.

The council said it was “assessing the extent of the damage and looking into the circumstances”.

The incident happened following an event at City Hall on Saturday evening to celebrate an Irish language group’s 20th anniversary.

Glór na Móna said they were “extremely disappointed” to learn of the incident and would assist the council with its investigation.

It said: “Following the formal end of our event, a portrait within city hall was damaged.

“Glór na Móna had no knowledge of this taking place and only became aware of this on Monday 21 October when contacted by council staff.

“This is completely contrary to the ethos and principles of our organisation and the spirit of our successful anniversary celebratory event.”

Several senior Sinn Féin members were among those seen in pictures posted online from the city hall event.

They included former party leader Gerry Adams and Aisling Reilly, a junior minister in the Northern Ireland Executive.

Sinn Féin was approached for comment.

In a statement the council said it hoped the portrait could be repaired “as soon as possible so the portrait can be put back on display”.

“The portrait of former Lord Mayor Lord Wallace Browne has been removed from public display after it was damaged over the weekend,” it said.

“We are currently assessing the extent of the damage and looking into the circumstances which led to the portrait being damaged.

“No further action has been taken at this time.”

The incident comes days after a portrait of former Belfast Lord Mayor Niall Ó Donnghaile was removed from City Hall.

Party group leaders on the council agreed the move unanimously, it is understood.

It followed revelations that Mr Ó Donnghaile quit Sinn Féin after sending inappropriate texts to a teenage boy.

Sinn Féin leader Mary Lou McDonald told the Dáil (Irish parliament) there were no findings of illegality and no criminal charges were pursued.

The DUP has called for a “full and robust investigation” into the portrait of Lord Browne being damaged.

Dean McCullough, the party’s deputy group leader on the council, said it appeared the portrait was “removed” from the wall and the glass was “smashed” within its frame.

The councillor questioned whether the portrait being damaged was “in any way linked” to the “rightful removal” of Mr Ó Donnghaile’s portrait.

“Further, it is worth highlighting that this particular portrait was painted by the renowned Jewish artist, Israel Zohar – again, raising another, serious question,” he said.

“Let us be clear, we will not tolerate the portraits of upstanding public servants, and Democratic Unionists, being damaged in our city hall.”