The security alert at Springhill Park in Strabane has now ended and the road has reopened.
Two objects were examined by ATO and declared viable pipe bomb type devices.
The devices have been made safe and removed for further forensic examination.
Detective Inspector Jenna Fitzpatrick said: “This incident has caused inconvenience and disruption for the local community and I would like to thank the members of the public for their patience and cooperation during the operation.
“An investigation is now underway to find those responsible for recklessly putting the lives of local people at risk by leaving these devices in a busy residential area.
“I would ask anyone with any information which could assist us with our enquiries to contact police in Strabane on 101 quoting reference number 412 25/11/16. Information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.”