Two wanted men were kicked and beaten with iron bars before they were apprehended, the PSNI has said.
James White and Alexis Guesto were also covered in paint after being detained by a gang of men in south Armagh on Saturday.
PSNI detective chief inspector Jill Duffie said: "We believe the two men, James White and Alexis Guesto, who were wanted by police for a range of offences, including breach of licence and warrants, were discovered by a group of males on Saturday evening as they attempted to evade an ongoing police search for them.
"White and Guesto were kicked and beaten with iron bars before being taken to Mullaghbawn village, where they were further assaulted by a number of individuals and covered in paint."
Both men were treated in hospital for their injuries.
One has been arrested while the other remains in hospital.
Ms Duffie said: "Both men will be brought before the court at the earliest opportunity in relation to the matters for which they were being sought."
It was believed the pair had travelled to Northern Ireland from the Republic.
Ms Duffie warned that resources had to be "redirected" towards investigating the serious assault.
She added: "Throughout yesterday as our search for the two men was ongoing, I was pleased with the response from the local community and the assistance being provided to police.
"Unfortunately, now, due to the violent actions of a small number of people, we have had to redirect resources and efforts towards investigating a serious assault.
"There is no excuse for individuals taking the law into their own hands nor for the violent scenes that we witnessed."