The shooting of an off-duty police officer represents an “attack on the peace process”, Sinn Féin vice president Michelle O’Neill has said.
Detective Chief Inspector John Caldwell remained in a critical but stable condition in hospital after being shot multiple times at a youth sports centre in Co Tyrone on Wednesday evening.
Dissident republican group the New IRA is the primary focus for detectives investigating the shooting.
The attack has sparked condemnation by political leaders and churches across the UK and Ireland.
Ms O’Neill said everyone is “at one and united” in condemnation.
“These actions are totally intolerable and not acceptable to anybody,” she told reporters at Stormont.
“They represent an attack on the peace process and everything that we have achieved over the last 25 years, and that can’t be allowed to happen.
“Here we are celebrating 25 years of the peace process, something that we all should be very proud of, and these people are attacking the peace process, it is as simple as that, and that is not tolerable to anybody.
“We’re all united as political leaders, as the PSNI, as leaders across this island and both islands.”
DUP leader Sir Jeffrey Donaldson said he understands Mr Caldwell remains “very seriously ill”, adding he is hoping and praying he will be able to recover.
He denied that the current political vacuum at Stormont could be connected to the attack.
“I believe that this was a carefully targeted attack, and we’ve seen that in recent times from dissident republicans in particular, and I think the clear message that we’ve sought to send out as political leaders is that there is unity amongst us in not only our condemnation, but our support for the police,” he told reporters at Stormont.
“I have already engaged with the Government on the need to ensure that the police have the resources they need, whether that’s in recruitment of additional officers or indeed other practical support that is required to ensure that the terrorists don’t have their way.”
Earlier Ms O’Neill and Sir Jeffrey, along with Alliance leader Naomi Long, UUP leader Doug Beattie and SDLP leader Colum Eastwood issued a joint statement of condemnation.
The political leaders in Northern Ireland said: “We speak for the overwhelming majority of people right across our community who are outraged and sickened by this reprehensible and callous attempted murder.
“The community of Omagh has endured profound suffering, loss and pain in the past which has left a deep trauma, and so this act of violence has left people there rightly angered.
“There is absolutely no tolerance for such attacks by the enemies of our peace.
“Those responsible must be brought to justice.
“This will require the full co-operation of the public whom we call upon to assist police in this attempted murder investigation.
“Together we stand with John’s family and his colleagues in the police service at this time.”
UK Prime Minister Rishi Sunak said he was appalled by the “disgraceful shooting of an off-duty police officer in Omagh”.
Taoiseach Leo Varadkar condemned the “grotesque act of attempted murder”.
President Michael D Higgins said: “The shooting of a police officer in front of his son is something that will be condemned by all those who believe in democracy and the peace that we all need to sustain.
“It is to be welcomed that members of all communities have expressed their revulsion at this act.”
On Thursday morning, Northern Ireland Secretary Chris Heaton-Harris described the attack as “cowardly and callous”.
He said the community of Omagh is “completely shocked by this because society has moved on in Northern Ireland”, adding: “There is no place for violence like this.”
Asked if he was concerned about the safety of PSNI officers, Mr Heaton-Harris said: “I’m always concerned about safety of PSNI officers, but they’re completely professional, and in all my experiences with them they know exactly what they’re doing and actually are policing the communities of Northern Ireland really effectively and very, very well.
“But this is a really significant event. It’s a very serious event, and it’s difficult to underline how cowardly these people are.”
He said he will be in Northern Ireland “very shortly”.
