Thousands of people are expected to take part in a lunchtime peace rally at Belfast City Hall today. It has been organised by the Irish Congress of Trade Unions following the recent upsurge in violence.
Rallies are also being held in Derry, Enniskillen, Lurgan, Antrim and Omagh.
Mr Tom Gillen, deputy Northern Ireland officer of the ICTU, said many groups and individuals had expressed support for the rallies. "We have had three decades of murders, bombings and shootings and recently there has been a very vicious upsurge at a time when people were hoping that things would improve.
"It is essential that we renew our message to the people who are doing this: to stop the killings and that you are not wanted in our society."
The leaders of the four main churches have issued a statement supporting the rallies. They also joined yesterday in signing the "Books for Peace" at Belfast City Hall.
The peace demonstrations are also being supported by the North's two universities, student unions, the Confederation of British Industry, chambers of commerce, district councils, the Women's Coalition and the Northern Ireland Council for Voluntary Action.
Meanwhile, Mr Tony Worthington, a Northern Ireland Office Minister, said the British and Irish governments had not ruled out the possibility that the Ulster Democratic Party could re-enter the talks "if, over a period of some weeks, a complete and unqualified ceasefire were demonstrated and established through word and deed".
UDP representatives are expected to meet British government officials in Belfast today. A spokesman for the party, which is linked to the UFF, said it hoped to be back in the talks before the end of next month.