Security and republican sources have blamed the INLA for shooting a Protestant teenager in north Belfast. The incident was followed by two gun attacks on nationalists, two attempted shootings and the murder of Catholic teenager Gerard Lawlor.
Mr Lawlor (19) was shot dead as he walked home from a pub on the Antrim Road early yesterday. The killing was admitted by the Ulster Freedom Fighters, a cover-name for the UDA.
In a statement admitting responsibility, it accused the security forces of not protecting Protestants and warned that attacks by nationalists would be "met with further military action".
Local nationalists said the shooting of the Protestant man on the Ardoyne peaceline followed sustained stone-throwing. A gunman opened fire on Mr Mark Blaney (19) as he stood in Glenbryn Park. He is "ill but stable" in hospital.
Sinn Féin Assembly member Mr Gerry Kelly said the Provisional IRA was not responsible but he could not speak for smaller republican groups.
Mr Paul Little, a spokesman for the INLA's political wing, the Irish Republican Socialist Party, said he had "no reason to believe" the INLA ceasefire was not intact. He said that loyalists had been mounting a campaign of violence against nationalists. Any violence from nationalists was "purely defensive and an inevitable response to loyalist aggression".
The North's First Minister, Mr David Trimble, said a relatively peaceful July 12th had been followed by "a dreadful few days". The Deputy First Minister, Mr Mark Durkan, said the killing was "evil and savage".