Three vehicles were damaged in an explosion on a driveway in Eastleigh, Hampshire.
Although no one was injured in the blast, police arrested a 56-year-old man and a woman aged 58 after the incident in Chadwick Road, both of whom belonged to the Eastleigh area.
Detectives from Hampshire Police conducted inquiries, while the Army's explosive ordnance disposal unit attended the scene which was cordoned off. No homes were evacuated.
Detective Chief Inspector Dick Pearson said: "The area has been searched and no other devices were located. We believe this was an isolated incident and there is nothing to suggest this was linked to any act of terrorism.
"The incident is being investigated as a criminal damage offence, recklessly endangering life. I would urge anyone with any information to get in touch with us to assist us with our investigation."
© Press Association 2010