Four men admitted to St James's Hospital in Dublin earlier this week have suffered serious burns ranging from 35 per cent to 55 per cent of their bodies, the hospital has said.
The men, believed to be brothers, were admitted from Louth County Hospital on Tuesday and will require treatment "for some time", a statement on behalf of St James's said today.
Gardaí and the PSNI are investigating a possible link to the attack in Co Armagh on Monday when a man and woman were seriously burned in an arson attack.
Both were severely burnt after they were doused with flammable liquid and set alight in an attack on Monday night near Keady, Co Armagh.
Police and politicians said the 21-year-old woman was "fighting for her life" after the attack which caused widespread shock and revulsion. "We are assisting the PSNI in any way we can," a Garda spokesman said.
The Armagh couple were attacked by a gang of five or six men at about 8.45pm at their home at Foley Road in Tassagh between Keady and Markethill. Both they and the house were doused with flammable liquid, which was then set alight.
The woman, who was enveloped in flames, managed to run up the road to a neighbouring house to raise the alarm. Neighbours dragged the man (33) from the burning house, which was destroyed in the fire.
Police said they were following a definite line of inquiry and were treating the incident as attempted murder. They said the attack did not appear to have been motivated by robbery, racism or sectarianism. They said they had not ruled out paramilitary involvement but that "it was not a major line of inquiry".