Portadown: Device 'found under soldier's car'
Upper Bann MP David Simpson said it was his understanding that the Army officer found the device earlier on Friday and that she phoned police.
Bomb disposal officers were called to scene and a number of houses have been evacuated.
'Serious situation' The bomb squad carried out a controlled explosion on the device at about 16:45 GMT.
Mr Simpson, who is a member of the Democratic Unionist Party (DUP), said it was a "very serious situation".
"We have to pay tribute to the diligence of the individual who discovered it.
"Today we could have been looking at a fatality, but the diligence was there and this device was discovered," the MP told the BBC's Evening Extra programme.
'Worrying development' Mr Simpson said he believed dissident republicans were responsible for the attack but added that this had not yet been confirmed by the security forces.
Justice Minister David Ford said it was a "worrying development".
"It shows the value of vigilance on the part of this individual officer. It shows the need for vigilance, but I'm absolutely delighted that clearly vigilance has paid off."
Mr Ford also praised the actions of the bomb disposal team.
'Evil act' Sinn Féin MLA John O'Dowd condemned the attack and said those responsible "do not speak for the local community and are not advancing any cause".
SDLP MLA Dolores Kelly said: "This was an evil act against an individual and those who carried it out have no regard for the safety of the wider public through their wanton recklessness for the lives of many."
The alert is continuing. Part of Corbracky Road has been closed to traffic and diversions are in place.
NWN: 'They' haven't gone away you know.