An off-duty police officer shot by masked men in Omagh has been named as Detective Chief Inspector John Caldwell.
The senior officer was shot multiple times in front of young people he had been coaching at a sports centre just before 8pm on Wednesday, in Co Tyrone.
Irish media are reporting police are searching for two suspects who were dressed in black.
The Police Service of Northern Ireland (PSNI) have launched an attempted murder investigation.
The force says the dissident republican group, the New IRA, is the primary focus of their investigation.
Assistant Chief Constable Mark McEwan told BBC Radio Ulster: “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.”
Mr Caldwell remains in a critical but stable condition in hospital following the attack on Wednesday evening.
He is 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.
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.
In a statement last night, the Garda said it is “currently responding to an ongoing incident which took place earlier this evening in Northern Ireland”.
“A Garda Siochana has intensified patrolling in border counties.”
Temporary Detective Chief Superintendent Eamonn Corrigan said: “Our investigation is now underway and I would appeal to anyone who was in the area and witnessed what happened or could help with our enquiries to make contact with police on 101.”
Liam Kelly, chair of the Police Federation for Northern Ireland, which represents rank-and-file officers, described the attack as “barbaric and cold-blooded”.
“The people who carried out this cowardly and shocking act must be quickly identified and apprehended and I would appeal to the community to assist the police in whatever way they can.
“My thoughts, and those of all police officers, are with our colleague and his family. The police family is strong and resilient, and we’ll be there for him and his family in this dreadful hour of need.”