Police were on Friday hunting those behind four bomb bids in Belfast within 24 hours amid fears of further attacks.
Explosive devices have been left under cars or close to homes at various locations across the city, with one exploding, causing major damage to a vehicle.
With no obvious security force target in each incident, the spate of bomb attempts have prompted concerns of a potential drugs turf war or a fall-out among criminal gangs.
An image captured of the latest device, which was found near homes in the Poleglass area of west Belfast late on Thursday night, appeared to show a plastic milk container filled with liquid attached by wires to some form of electronic timer.
Police have refused to be drawn on the potential motive, but have warned that the devices had the potential to kill.
PSNI Chief Superintendent Nigel Grimshaw said all of them were similar in design.
“Clearly the type of device that was used was designed to either cause serious harm to somebody or to kill somebody and that’s exactly what would have happened had they detonated with somebody in close proximity,” he said.
“When people put these sort of devices out on the street they are absolutely reckless, they have no regard whatsoever to innocent people going about their business - it could have been a child, it could have been an elderly person, it could have been anybody who could have been seriously hurt, it could have been police officers.
“So this is something we take very seriously.”
Mr Grimshaw appealed for public help to catch the bombers before they strike again.
“Policing is there to make sure these things don’t escalate,” he said.
“I am working to try and make sure that we don’t see any more but it would be foolish at the end of the day to not consider the possibility.”
Police have been criticised for the length of time officers have taken to attend the scene of two of the incidents.
Mr Grimshaw said he had asked for a review of the police’s handling of the security alerts but stressed that officers were working under a severe threat from dissident republicans and had to approach each incident with that in mind.
He rejected the suggestion there were some no-go areas for the police in Belfast at night time.
The discovery in the Colinbrook area of Poleglass on Thursday night came after three similar devices were found earlier in the day in Belfast.
The security alert in Colinbrook required a number of residents to be evacuated from their homes during the early hours of the morning while Army bomb disposal officers made the device safe.
No-one was injured when a device went off under a car on St James Road, off the Falls Road in west Belfast, just before midnight on Wednesday.
The incident was originally treated as a car fire and was dealt with by the Fire Service, with the remnants of the bomb only discovered yesterday morning when the vehicle was moved.
An unexploded pipe bomb found in Friendly Street in the Markets area of the city centre was also placed under a car while another similar device was left on the pavement in North Queen Street in the north of the city.
Both those bombs were made safe by Army technical officers.
Sinn Fein councillor in Poleglass Stephen Magennis, who released the image of the device, said those who left it had shown “complete and utter disregard for the local community”.
He said: “Residents are extremely relieved that this device failed to go off, a device that could have caused serious injury.
“It seems that this device is linked to other devices which were left in St James’, the Markets and North Queen Street yesterday causing significant disruption to communities across Belfast.
“The only effect these devices have was to place residents in danger and force many to leave their homes.
“Those behind it need to come forward and explain their actions. I have no doubt however that they won’t and will continue to hide.”