A suspected explosive booby trap went off right outside the house of a man in Blaney Road, Crossmaglen, Co. Armagh, causing severe injuries to him.
The explosives were wired to a poster which the man was trying to remove. The poster reportedly depicted offensive information personally targeted at him.
The victim, Thomas McCabe, is the son of prominent republican Frank McCabe. He is undergoing emergency surgery, and it is understood he may lose an eye over the incident.
Sinn Féin MP Conor Murphy has claimed that the poster was erected by an organised crime gang in the South Armagh area.
The Blaney Road from Loughross Road to the border remains closed.