Dissident republicans attempted to use a booby-trapped bomb to murder police officers in Craigavon, the PSNI has said.
At around midnight on Friday police received reports of a loud bang in the Tullygally Road area. A short time later a Belfast-based newspaper reported receiving a call claiming a mortar had been fired at a police patrol.
Police believe both reports were designed to lure officers into the area.
Officers responding found a viable device close to a public bus stop that had been designed and set up to look like a fired mortar. In reality, however, it was a booby-trapped bomb, intended to explode if moved or touched.
Detective Superintendent Richard Campbell said: "Had it detonated, as those responsible for placing it had intended, the result would undoubtedly have been catastrophic for anyone in the immediate vicinity.
"On Friday night this included people out socialising, teenagers and residents attempting to simply go about their daily lives.
"This attack was indiscriminate. Whilst there is no doubt in my mind that first responders were the target, the reality is that anyone could have been caught up in the carnage.
"We are extremely fortunate that the swift actions of those officers who were first on scene meant that there was not serious injury or death."
Detective Superintendent Campbell said the incident emphasises the importance of members of the public reporting anything suspicious they may see to police.
"I would like to again thank the community for their patience and cooperation throughout the security operation as we sought to ensure their safety," he added.
"I ask that anyone who may be able to help our investigation and identify the perpetrators of this evil and wicked attack to please come forward.
"You can call us on 101 or if you would prefer information can be given anonymously via the independent charity Crimestoppers on 0800 555 111.”
Mark Lindsay, chair of the Police Federation for Northern Ireland, warned the incident could lead to slower police response times, as officers will have to exercise "even greater levels of caution".
"Officers operating in particular areas already exercise great caution. They are forced to risk assess and evaluate, and that, unfortunately, can lead to delays in responding to genuine calls from the public," he said.
“On the back of this cold-blooded act at midnight on Friday, officers will have to be even more cautious. No one expects officers to leave themselves vulnerable to terrorist attacks, and that must mean the very real prospect of slower response times."