Dissident republicans are believed to have been behind a mortar attack on a British army base in Co Armagh late last night.
A loud explosion was reported in the town of Bessbrook, in south Armagh at just before 11 p.m.
After further investigation, police found a van left abandoned in a field to the rear of the base in the old Bessbrook mill.
The Assembly member for the area, Mr Danny Kennedy of the Ulster Unionist Party, said it appeared at least one mortar had been fired from the van at the army base but there were no reports of any injuries or serious damage.
British army bomb disposal officers were examining the van and another suspect device and those living in houses around the base were evacuated. It was not clear last night how many mortars had been fired, if they had been fired successfully and if any shells fired had exploded.
Security forces have warned they expected dissident Republicans to increase their operations in the North and Britain in the run-up to the Westminster elections on June 7th.
Mortars have been fired by dissidents at a number of security bases in recent months and security sources have expressed concern at the increasing expertise demonstrated in their construction and use.
A man has died in hospital after being stabbed in Belfast at the weekend.
An RUC spokeswoman said the man, named as Mr Damien Kennedy (37) was attacked in a house in Beechmount Grove in the west of the city on Sunday.
A 37-year-old woman appeared in court on Monday charged with the attempted murder of Mr Kennedy.