Yobs can be seen throwing metal barriers at a coach waiting outside the ground, while chanting Football’s Coming Home, in video footage of the ugly scenes that has been shared online.
South Wales Police said they were investigating the unrest following the standoff on Saturday August 14.
A force spokesman said a policeman was lightly injured and a man was arrested on suspicion of assaulting a steward.
They added: “Officers are working with stadium management to review CCTV and anyone with information is asked to contact us quoting the occurrence 2100227115.”
Sheffield United fans have condemned the “pathetic” behavior of the small contingent of supporters from both sides who clashed after the Championship game.
One wrote on the S2 4SU forum: “I’m never in awe of hooliganism, but the post game against Swansea was particularly pathetic.
“Two sets of fans safely separated by a fence where the trainers were parked, challenging ‘the other side’ to a fight.
“At one point one of our ‘fans’ climbed over the fence and realized that if he had jumped over it he would have been left to his own devices with about 20 ‘fans’ of Swansea and changed his mind.
“It’s a bit like going to Yorkshire Wildlife Park and challenging the lions to a safe fight knowing they can’t get to you!”
A Swansea City spokesperson said: “Swansea City are extremely disappointed with the behavior of a small portion of the home and away supporters following Saturday’s Championship game at Swansea.com Stadium.
“The images circulating on social networks show totally unacceptable behavior. This will not be tolerated by the club and we are working with South Wales Police to identify those affected so that appropriate action can be taken.
“As a club, we have worked tirelessly for many years to ensure a safe and enjoyable match experience for home and away fans, and we will issue further communications in due course regarding behavior during matches. matches.”
The Star has contacted Sheffield United for comment.