Two devices have been taken away for forensic examination following security alerts in Camlough and Maghery.
These devices were of crude construction, but could have caused serious harm, according to police.
Chief Superintendent Andy Freeburn, South Area Commander said police are at the very early stages of an investigation and are keeping an open mind as to the motive.
“I would like to thank local communities for their support and patience as we worked to keep people safe.
“We are keen to hear from anyone who may have noticed any unusual activity or anything out of the ordinary in either the Newtown Road area of Camlough or in the vicinity of Milltown, Maghery prior to 22 March. Please call us on 101 or you can contact Crimestoppers anonymously on 0800 555 111,” he added.