Four people were taken to hospital with head injuries following an alleged "violent disorder" on Saturday evening.
A police officer was also treated after being assaulted at the scene.
Gwent Police confirmed they responded to reports of "serious disorder" on Frogmore Street in Abergavenny at around 5.40pm on Saturday, June 22.
A force spokesman said: "Officers arrested five men on suspicion of assault and violent disorder."
Those men are currently in police custody.
Four people are currently being treated at Nevill Hall Hospital for head injuries.
The police officer who was assaulted returned to duty following treatment.
Officers remained in the area throughout the evening.
Gwent Police are appealing for witnesses and anyone with information is asked to call the force on 101 with reference 383 of June 22.
Witnesses can also call Crimestoppers anonymously on 0800 555 111 or contact police through their Facebook and Twitter accounts.
