Republican dissidents were behind Tuesday night's mortar-bomb attack on a British army barracks in Bessbrook, Co Armagh, according to an Ulster Unionist MLA, Mr Danny Kennedy.
The "Real IRA" carried out the attack in response to yesterday's US fund-raising ban on the organisation, he said.
The attack was deplored by politicians across the political spectrum. A Sinn Fein MLA, Mr Connor Murphy, said those responsible enjoyed no support within the community.
Residents were evacuated from Camlough Park in the town at about 10 p.m. on Tuesday after a loud bang was heard in the area.
Yesterday morning residents in Fountain Street were also moved out of their homes, bringing to 80 the number of families evacuated.
A mortar was fired from a van parked outside the town's community centre, according to police at the scene. It travelled 40 or 50 metres before falling short of its target, Bessbrook Mill army base. The mortar landed on waste ground and failed to explode.
A security operation was continuing last night as army technical officers examined both the van and mortar. Two controlled explosions were carried out.
A church hall was used to accommodate some of those evacuated from Camlough Park. A Presbyterian minister said about 20 people, several of them in their 80s, stayed in the hall for two hours while waiting to be collected by friends and relatives.
In a joint statement the First Minister, Mr David Trimble, and Deputy First Minister, Mr Seamus Mallon, said the attack had caused unacceptable inconvenience to the people of Bessbrook.
"We strongly condemn those who are responsible. They have taken no interest in the careless risk to life and potential for injury created by such an indiscriminate action," they said.