Security patrols, including undercover activity, have been stepped up following the spate of attacks which left three men dead in a 36-hour period. In all, seven have been killed since 27 December, including five Catholic civilians and two loyalist activists.
The violence has brought a wave of condemnation together with calls for politicians not to be deflected from the Stormont multi-party talks. Moving appeals have also been made by relatives of the dead for an end to the killings.
On Monday the killing of the loyalist Jim Guiney by the Irish National Liberation Army in the morning was followed by the killing of the Catholic taxi driver Larry Brennan that evening. Mr Brennan, 52, was engaged to a Protestant woman. His 71-year-old mother, Mary, said yesterday she was sure she would die of a broken heart. In 1972 one of her nephews was killed by loyalists.
Mr Brennan's sister, Mrs Eilish O'Reilly, said she did not want anyone else to die, adding: "I don't want anybody to take anybody's life in the name of my brother. All this has to stop. I know sometimes when you say this people don't listen - but nobody is to take any reprisals in the name of my brother.
"He was engaged to a girl who was a Protestant, his best friends were two Protestant men. He always thought that if he minded his own business and didn't do anybody any harm he would always be all right."
The prime suspects for his killing are the Ulster Defence Association, the paramilitary group with which Jim Guiney was linked. Security sources believe the UDA carried out the killing or gave the go-ahead.
The Sinn Fein president, Gerry Adams, accused the UDA of being involved in some of the recent killings, alleging the organisation had a "no claim, no blame" policy. But he would not demand the expulsion of the Ulster Democratic Party, the UDA's political wing, from the Stormont talks. "We have always held the view that the loyalists and everybody else should be involved in these discussions, all of us."
The UDP leader, Gary McMichael, said in response that he had no evidence of UDA responsibility for the shooting. The Ulster Unionist leader, David Trimble, condemned the loyalist violence, describing those responsible as "criminal fools" who were being manipulated by republicans. "They are doing the work of republicans."
The Prime Minister's official spokesman said Mrs O'Reilly's words had struck a chord with Mr Blair: "He felt she spoke for what he feels most people think - that this kind of tit-for-tat killing is horrendous. When you have the families saying `For God's sake stop', people will hope that may have some influence. Our sense is that people involved in the talks process want that to be the place where all the arrangements are put in place."