The so called GHQ faction of the INLA has admitted that it shot Mr Sean McEvoy in west Belfast in the early hours of Saturday.
In a coded statement to a local radio station, a caller said the GHQ staff group carried out the attack in New Barnsley.
Mr McEvoy (32) was seriously wounded when a gunman opened fire on him with a rifle as he left a friend's house. He remains critically ill in hospital.
