Police patrols are being stepped up following complaints of bikers targeting the Swansea city centre area.
Officers have received reports of bikers tearing over the grass verges with residents branding the riders as “idiots”.
One local, Debra Brooks, blamed the parents of the youths involved for shelling out for the bikes in the first place.
She said: “Those bikes are not cheap, the parents of those kids know exactly what they are doing… it’s not as if they can sneak off with bikes and the parents don’t know!”
Julian Davies spoke out after the riders were spotted driving all over the roundabout and is also unhappy about littering in the area.
He said: “This makes me mad. And what about over the last couple of days with people also leaving the rubbish all over beaches and parks.”
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A South Wales Police spokesman said: “We have had two incidents reported to us of ASB (anti-social behaviour) and motorbikes in the city centre.
“One was on the 1st April on Oystermouth Road and the other was the 3rd April on Waun Wen Road.”
He said both incidents were investigated and officers are making regular patrols in both areas.
“We would encourage anyone who has concerns connected to off road bikes in their area to report them to us via our online portal https://bit.ly/SWPReportOnline or by calling 101.”