Miss McKee, 29, died as a result of injuries sustained when she was shot in Fanad Drive on Thursday, 18 April.
In a statement given to
The Irish News via a recognised code word, the group offered their "full and sincere apologies" to her family and friends.
https://twitter.com/PA/status/1120474499512766471
The statement said: “On Thursday night following an incursion on the Creggan by heavily armed British crown forces which provoked rioting, the IRA deployed our volunteers to engage.
“We have instructed our volunteers to take the utmost care in future when engaging the enemy, and put in place measures to help ensure this. In the course of attacking the enemy Lyra McKee was tragically killed while standing beside enemy forces.
“The IRA offer our full and sincere apologies to the partner, family and friends of Lyra McKee for her death.”
The New IRA is an amalgam of armed groups that are opposed to the peace process and it recently claimed responsibility for parcel bombs sent to London and Glasgow earlier this year.
The senior detective leading the investigation into the murder of Miss McKee has revealed that more than 140 people have contacted police with information via the Major Incident Public Portal (MIPP).
Detective Superintendent Jason Murphy has said: "This was an attack on the community. Lyra, tragically, was a random victim and I need the public to continue to support us. Many witnesses have contacted us to give us information that has been provided to them. More than 140 people have contacted us via our MIPP with messages, including mobile phone footage. House-to house enquiries are continuing, and all of that is to be welcomed.
"I want to reassure people that you don’t have to commit to anything today. I just need to speak to people to understand what they know. We can then look at how we capture that information in the best way possible to protect those witnesses and enable me to bring the gunman who killed Lyra McKee to justice.”
He adds: "If you have information, no matter how small, please contact detectives in the incident room on 101 or via the Crimestoppers charity on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.
“I am continuing to appeal for those people who were in Fanad Drive and Central Drive on Thursday night and who have mobile phone footage to please come and speak with my detectives and provide us with your mobile phone footage. We do not need to hold on to your phone, we have necessary equipment that will allow us to download the footage quickly. Alternatively, you can use the Major Incident Public Portal at
MIPP.police.uk to upload footage or to tell us what they know.”
