A man has been treated in hospital after being stabbed in Crossmaglen, County Armagh, on Sunday.
The man in his 40s suffered deep cuts to his hand and a number of more superficial wounds to his head and neck, police said.
Officers were called to a bar in Concession Road at about 21:20 BST.
A 44-year-old man was arrested on suspicion of grievous bodily harm with intent and possession of an offensive weapon in a public place.
Det Sgt Doherty said a “number of people were present at the time of this shocking attack”.
“Several of them bravely restrained the perpetrator,” the officer said.
Police appealed for witnesses to contact them.