|PIC1|In a joint statement, the Archbishop of Armagh, the Most Rev Alan Harper, and the Archbishop of Dublin, Dr John Neill, said they were "shocked and outraged" at the killings.
"The people of Ireland North and South have agreed to move forward through political process," they said.
"The Good Friday Agreement signed by political representatives was confirmed in referenda that established a commitment to forge a peaceful, inclusive and respectful future.
"The actions of an unrepresentative minority will not be allowed to disrupt the democratic process and turn us back to darker days."
Sapper Mark Quinsey, 23, from Birmingham, and Sapper Cengiz Azimkar, 21, were shot dead by Real IRA gunmen as they collected pizzas at the gates of the Massereene Army base on Sunday night. On Monday night, Constable Stephen Paul Carroll, 48, was shot and killed by the Continuity IRA at Lismore Manor, Craigavon, in County Armagh as he responded to a call from a woman for help.
Archbishop Harper said the murderers were "evil people" who had committed "perverted acts". He called on the Church of Ireland to set Sunday aside as a day to remember the victims.
The Archbishop also appealed to anyone with information to go to the police and urged loyalists not to retaliate with violence.
"Such action would only play directly into the hands of the people responsible for what has happened. Violent acts do not serve the legitimate political aspirations of anyone on this island," he said.
"I encourage all to support the legitimate forces of law and order and demonstrate that as a community we have now moved beyond the barren responses of a blighted past. May the Holy Spirit of God give us the vision and the strength to serve His purposes alone."
The Church of Ireland Bishop of Connor, the Rt Rev Alan Abernethy, and the Catholic Bishop of Down and Connor, Mgr Noel Treanor, have paid hospital visits to the injured survivors of the attack at the Massereene Barracks.
They warned that anyone who used violence to achieve political means would "wreck our future and destroy hope".