DIY road markings on a corner beset by traffic problems have been branded "stupid" and "utterly disrespectful".
"Keap Claer plz" and "Keep Kleere plz" have been painted on the junction of Windermere Road and Rockliffe Road in Linthorpe, Middlesbrough.
Council teams were due to paint double yellow lines on the corner, but the Covid-19 outbreak has delayed the work.
Deputy mayor Antony High criticised the move and asked residents to contact the council to help track down the culprit.
He said: "It is utterly disrespectful to our town. If we find who this person is, we will be taking legal action.
"We still need to function as a council and there are certain things we just cannot accept.
"People just taking it on themselves to paint lines is something we will challenge.
"It's inappropriate, it's a waste of resources to fix it and the finances are tight enough without having to address anti-social behaviour."
Linthorpe councillor Philippa Storey had requested double yellow lines back in October in response to cars parking over dropped kerbs and access issues for emergency vehicles.
She said: "That's why I can understand the frustration because it is terrible.
"You do get some idiots who do park there, and regular cases of bin lorries not being able to get in."
The Local Democracy Reporting Service said double yellow lines were expected to be painted at the junction after the coronavirus restrictions were eased and the illegal markings removed.
The road markings were cleaned off on Wednesday afternoon as the council revealed it was bringing back some of its "area care" services.
Non-essential operations like grass cutting were put on hold last month in response to the coronavirus pandemic but the authority has said some services can be reinstated, with appropriate risk assessment and equipment.