Police were called to The Crescent, Brynmawr, at around 5.50pm on Monday 7 October, following reports of a dog attack.
Officers attended and a 12-year-old girl was taken to hospital with life changing injuries.
The dog was seized by officers and will be destroyed. No other animals were involved in the attack.
A 37-year-old man and a 42-year-old woman, both from the Brynmawr area, have been arrested on suspicion of owning or possessing a dog bred for fighting and owning or possessing a dog dangerously out of control.
They remain in police custody at this time.
Superintendent John Davies said:
“This was a distressing incident for those involved. I would like to reassure the local community there is no further risk to the public.
“It is possible that you may see ongoing police activity in Brynmawr as part of this work. You may have also seen an increased presence earlier this evening while officers were attending the incident.
“If you have concerns or information, please stop and talk with us.”
Anyone with information is asked to report through the website, direct message on social media, or call on 101, quoting reference 2400334368.
Alternatively, you can contact Crimestoppers anonymously by calling 0800 555 111.