Bloody Sunday: Londonderry's Guildhall memorial window in jeopardy
Relatives of some of those who died on Bloody Sunday in Derry have threatened to withdraw support for a memorial project.
Four stained glass windows were to be installed at the Guildhall.
Some families objected to an image that showed some victims against a backdrop of jubilant scenes following the release of the Saville report.
John Kelly, from the Bloody Sunday Trust, said the objection was "embarrassing".
Mr Kelly said he and five other families will remove their support for the entire project if the window is altered.
Sinn Féin criticised an SDLP motion passed by Derry City Council on Tuesday that will allow for the window to be installed with changes made.
Mr Kelly, whose brother Michael was killed on Bloody Sunday, said: "I feel sad that I have to justify the window and its contents when tomorrow is the 43rd anniversary of my brother's death and all those who died on Bloody Sunday and to a degree it's embarrassing.
"This is nothing to do with politics whatsoever. I approached Derry City Council with other family members to replace the previous window, which was grotesque.
"All the families had an opportunity to look at the window. Afterwards people came and objected, it was taken on board and it's been changed since then.
"There's no jubilation within that picture. This is a beautiful piece of art on behalf of the victims of Bloody Sunday.
"If they want to put up an altered picture then I have informed Derry City Council that I want my brother Michael's face removed from the window. Five other families will do the same."
Kate Nash, whose 19-year-old brother William was shot dead on Bloody Sunday, said she was one of several families to object to the image.
"The fourth panel has images of three of the victims on it and in the background there is a scene from the 15 June 2010, scenes of joy.
"Our contention is that it does not belong on a memorial window where we are depicting a tragedy that happened in 1972.
"It is not the place for those kind of scenes. It's inappropriate."
Thirteen people died when British soldiers opened fire on civil rights marchers in Derry in 1972. Another man died five months later.
In 2010 the Saville report found the killings had been "unjustified and unjustifiable" and Prime Minister David Cameron made a formal apology.