A device was left near the Dungannon Army base
Northern Ireland's police chief has warned there could be further attacks by dissident republican paramilitaries in the next few days because of Wednesday's assembly election.
Hugh Orde was speaking following a bomb attack near an Army base in County Tyrone, which followed a telephone warning from the Continuity IRA.
Two police officers narrowly escaped injury when the device, containing up to 60lbs of explosives, partially detonated in Dungannon.
A member of the public had walked past the device shortly before the blast which occurred at about 2200 GMT on Monday.
Mr Orde said the police were ready to meet any threat from dissident republicans during the 26 November poll.
"We have treated it very seriously, we have always taken the election very seriously," he said.
"I have over 2,000 officers policing the election tomorrow to make sure people can carry out their democratic right without fear of intimidation. We think there may be more problems within the next 24 or 48 hours."
A security alert swung into action on Monday night after a priest received a telephone warning from a man claiming to be from the Continuity IRA, who said a car bomb had been left at the Killymeal Road Army base in Dungannon.
However, no suspect vehicle was found.
Hugh Orde warned of possible further attacks
A man subsequently told the police he had walked past a suspicious device on the road.
Two police officers found the device and the area was evacuated.
Superintendent Ken Henning of the PSNI said: "Had the device went off in its entirety we could be dealing with two very seriously injured, or maybe two dead police officers.
"As well, we could be dealing with a dead member of the public who was out for a walk minding his own business and walked past this thing sitting on the footpath."
Army bomb experts were called to the scene and a nearby leisure centre was evacuated.
The remainder of the bomb was made safe shortly before 0100 GMT on Tuesday.
A number of items were taken away for further examination.
Meanwhile, in a separate incident, shots have been fired at a police station in Armagh.
Several shots were fired at the station on the Newry Road just after 2130 GMT on Monday.
It is believed the shots were fired from a passing vehicle. No-one was injured.
Northern Ireland Secretary Paul Murphy condemned the attacks.
"Last night's attacks on PSNI officers will be greeted with contempt right across the community," he said.
"Police officers work on behalf of the whole of society and an attack on them is an attack on all of us."