Up to 7,000 people have attended a peace rally in Belfast following the murder of policeman Ronan Kerr.
They gathered at City Hall for a demonstration organised by the Irish Congress of Trade Unions (ICTU).
Pamela Dooley, vice chair of the Northern Ireland committee of the union, said the new recruit was a fine public servant.
"He understood the risk he was taking to build a fairer, more just and equal society. He was prepared to take that risk and paid a terrible price for his courage," she said.
She added that everybody needed to work together without fear of intimidation, violence or death.
"Here today, in Ronan Kerr's name, we pledge to strive for a society where the hurt of the past is given proper expression through truth and justice and to build a future where no-one, especially our new generations, will ever again believe that violence has any place in building that future."
There has been unanimous cross-community condemnation of Saturday's car bomb murder in Omagh.
A moment's silence was held and then Billy Doherty, from the Tullintrain pipe band in Co Londonderry, played the pipes.