Newport County have apologised after fans allegedly mocked Bradford City over the 1985 Valley Parade fire tragedy in which 56 people died.
The Bantams have also complained to the Football Association about alleged abusive behaviour towards boss Stuart McCall during their loss in Newport.
McCall's father was badly burned in the fire.
Bradford say Newport chiefs have told them Gwent Police are investigating alleged 'repulsive chanting'.
The disaster took place on 11 May, 1985 when the main stand burned down after what was thought to be a dropped cigarette led to flames which engulfed the entire wooden structure.
In a statement Bradford said McCall was targeted during Saturday's game at Rodney Parade.
"McCall was approached by a supporter, carrying a Leeds United flag, who is understood to have verbally abused the Bantams boss," the statement read.
City's director of communications, Ryan Sparks, added: "We are absolutely disgusted by what our manager and club were subjected to on Saturday afternoon.
"Such repulsive chanting should not be tolerated by anyone and we have made our position clear to The FA.
"The Valley Parade Fire Disaster was without a doubt the darkest day in our club's proud, 117-year history.
"We were astounded to witness the tragedy - which continues to cause anguish to hundreds of people - being mocked, with stewards in close proximity appearing to leave the incident unchallenged.
"We would like to take this opportunity, however, to thank Newport County for their response."
In their response, Newport apologised and pledged "appropriate action" will be taken against "those identified" for their involvement.
"NCAFC would like to apologise unreservedly to Bradford City AFC and more so Stuart McCall for the unsavoury actions towards Stuart at Rodney Parade on Saturday.
"These actions have no place in society, let alone in our football club and chairman Gavin Foxall has been in dialogue with Bradford officials and spoken personally to manager Stuart McCall to offer an apology on behalf the club."
Newport manager Michael Flynn, a former Bradford player who had been signed by McCall, said: "I think the club have handled it exceptionally well and I would like to obviously say from my behalf that I am very sorry for what was said, because Bradford is a club that means a lot to me.
"And the club are doing all they can to make sure that the individual or people involved are banned from this football club."
A Gwent Police statement said: "We were contacted about this by Newport County AFC on Monday, 24 February. Officers are now investigating this as a public order offence and will be liaising with both clubs and reviewing CCTV to identify the offenders.
"Anyone with any information can call us on 101 quoting log number 201 25/02/20 you can also direct message on Facebook or Twitter or call Crimestoppers on 0800 555 111."