The senior police officer shot in Omagh has been named as Detective Chief Inspector John Caldwell as police said the primary focus of the investigation is on dissident republicans.
Mr Caldwell remains in a critical but stable condition in hospital after the attack at a sports complex in Omagh, Co Tyrone, on Wednesday evening.
He was shot a number of times by masked men in front of young people he had been coaching at the Youth Sports Centre.
His young son was with him at the time, police said.
Mr Caldwell was a high-profile officer who has led a number of major investigations, including taking a leading role in the murder probe following the killing of Natalie McNally in Lurgan in December.
The Police Service of Northern Ireland (PSNI) have launched an attempted murder investigation.
Assistant Chief Constable Mark McEwan told BBC Radio Ulster the “primary focus” of the investigation is on “violent dissident republicans”.
He said: “The investigation is at an early stage, we are keeping an open mind. There are multiple strands to that investigation.
“The primary focus is on violent dissident republicans and within that there is a primary focus as well on New IRA.”
Irish police are working closely in co-operation with their counterparts in the PSNI, and have intensified patrols amid suspicions the gunmen may have fled across the border.
Christos Gaitatzis, the principal of Omagh High School whose students were at the scene of the shooting, told BBC Radio Ulster: “I can only imagine how difficult it must be for the youngsters this morning, waking up in the aftershock of what they experienced last night.
“I feel that those people affected here last night were my children, were my family. We really need to get together as a community in order to make sure that these types of instances, that contain violence in the most heinous way I can describe, have to be pushed away from our community.
“(We have to) make sure that those individuals are caught and isolated out of our community to make sure that Omagh remains the town that it always has been – a town that is together, is coming together at all times, especially during difficult circumstances like this.”
The New IRA was previously blamed for the killing of journalist Lyra McKee in Londonderry in 2019.
Last November, the group was thought to be behind the attempted murder of two police officers in a bomb attack in Strabane, Co Tyrone.
Omagh has seen significant dissident violence in the past, including a Real IRA bomb attack in 1998 which killed 29 people, including a woman pregnant with twins.
It was also where Constable Ronan Kerr was murdered in April 2011.
The terrorism threat level in Northern Ireland was lowered from severe to substantial for the first time in 12 years last March.
The shooting of Mr Caldwell has been condemned by politicians across the UK and Ireland.
Prime Minister Rishi Sunak said he was appalled by the “disgraceful shooting of an off-duty police officer in Omagh”.
Irish premier Leo Varadkar condemned the “grotesque act of attempted murder”.
Sinn Fein president Mary Lou McDonald said the shooting was “diabolical and unacceptable”, and added there is no excuse or political rationale for it.
She told RTE: “There can be no hiding place for this. There can be no sympathy for this. There is no rhyme or reason politically speaking for a vicious act of thuggery like this.
“Now what we need is an all-Ireland effort co-operation between An Garda Siochana and the PSNI to find the motive for this act, and more importantly to apprehend the perpetrators and anybody with any evidence or any information must not hesitate in bringing that forward immediately to the appropriate authorities.”
