Update 4pm: New Garda Commissioner Drew Harris has attempted to quash concerns about his links to British intelligence services, saying he has reported wrongdoing by security forces on "many occasions".
On his second day in the role, the 53-year-old addressed concerns about his key role within MI5 - saying that he always worked to "prevent and detect" crime.
The former deputy chief constable of the Police Service of Northern Ireland (PSNI) was asked about his previous roles as he takes the lead role in An Garda Síochána.
"I've always been a police officer, it has always been my responsibility to prevent and detect crime and I have always done that," he said.
"If any time I have ever found any wrongdoing of any nature, involving anyone and in this case which finger points towards wrongdoing by security forces, it would be my responsibility to report that to Police Ombudsman and I have done that on many occasions where I felt there was wrongdoing."
Commissioner Drew Harris at a sit down introductory press briefing in Garda HQ this morning, 4th September 2018. pic.twitter.com/gG63lh67Gt— Garda Info (@gardainfo) September 4, 2018
Mr Harris addressed the media for around 30 minutes on Tuesday at the Garda Headquarters in Phoenix Park in Dublin.
He referred to a number of concerns that have been raised following his appointment to the role of Commissioner.
A number of survivors and victims of Loyalist attacks questioned his suitability because of his previous role in the PSNI and Royal Ulster Constabulary (RUC).
"I'm very aware of the concerns some have raised, throughout my policing career I have acted with impartiality, I have brought many loyalist terrorists to justice and I have secured convictions - and these crimes have been atrocious crimes and I have been diligent and persistent in the investigation of those," he added.
"I understand the hurt that remains with those victims. I can assure them of my integrity in what I was doing as a PSNI officer and RUC officer."
Mr Harris is the first Garda Commissioner to be appointed from outside the State.
When asked whether he considers himself Irish, he said: "Yes, I am Irish.
"I'm not sure how much of an outsider I am really. I'm a police officer, I'm from the island of Ireland and have worked for the benefit of people of Ireland.
"I'm here to lead the organisation."
He added that he believes politicians are "fully behind" him in his role as commissioner.
When probed further about his intelligence regarding terrorist murders in Ireland and his obligation to pass on information, he said that he has "no other" intelligence to share with the Gardaí.
He added: "That obligation would have been a live obligation with the PSNI. Intelligence is constantly exchanged between both police services or via the security service.
"I could highlight numerous cross-border operations where we exchange very sensitive intelligence and work very closely on joint operations and that prevented many terrorist outrages and very serious organised crime.
"The matters I was aware of with PSNI are always dealt with properly."
He said he is here "to protect the people of Ireland" and will serve the public in "good faith".
Mr Harris said that dissident republicans remain the biggest threat on the island of Ireland and are "determined" to carry out attacks.
He raised a number of areas he will focus on over the coming years - including the threat from dissident republicans, organised crime and the threat from international terrorists.
He also spoke of his plans to address how Garda Síochána is spending its budget and how it will deal with Brexit.
"This is an area of focus, our planning process is under way. Not all of the responsibility of Brexit, of whatever nature, will fall to Garda Síochána, but we have to be concerned with police-to-police cooperation at a local level with PSNI and how we secure border areas and we have to be aware of organised crime," he added.
- Press Association
The new Garda Commissioner says dissident republican groups remain the biggest threat to the island of Ireland.
Drew Harris has given his first press conference where he discussed garda resources, organised crime and Brexit.
The former deputy chief constable of the PSNI took up the job early yesterday morning.
Commissioner Harris say republicanism is one of his major concerns.
"They remain the greatest threat on the island of Ireland. They pose a threat and continue to do so," he said.
"There's been a lot of success against them, a lot of that threat has been eroded and diminished but we are very aware that these people are full of intent and determination to carry out attacks."
Update 12.10pm: The new Garda Commissioner says he does not view himself as an outsider.
Drew Harris has given his first press conference where he discussed garda resources, the Hutch Kinahan feud and the threat of republicanism.
The former chief constable of the PSNI is the first external candidate to become head of the gardaí.
He says he views himself as one of team.
"Yes I am Irish," he said.
"I'm not sure how much of an outsider I am really.
"I'm a police officer, I joined a police organisation. I'm from the island of Ireland.