The daubing of IRA slogans on a mural and homes in Londonderry has sparked anger.
The mural at Bonds Street in the Waterside was defaced with the words 'IRA ghost' in white paint in the early hours of Sunday.
The same slogan appeared across the doors of eight houses in nearby Duddy's Court, a shared housing area in the Waterside.
One resident said people in the area were fearful that matters could escalate.
He said: "Waking up on a Sunday morning to see a huge letter on your front door is not what anyone wants.
"This didn't happen in a few seconds, whoever did this took time to go to eight different houses and do this, and what the hell is 'IRA Ghost' anyway? What does that even mean?
"This is a mixed area, but neither community wants to see sectarian attacks, either here or in Bonds Street."
Across the road in Bonds Street people were just as anxious about the possibility of more attacks.
"This was a quiet area up until recently," said one woman who has lived there for over 30 years.
"That mural was put there not all that long ago and there is nothing there that anyone could take offence at, but some thug has.
"I am worried now that the young boys around here will take it upon themselves to do something to the other side in retaliation, and then you are left with a whole handling and we are back to where we were 20 years ago."
The graffiti attacks were condemned by local politicians.
DUP councillor David Ramsey said: "People in Bonds Street have all said they realise what is behind this and they know they are being goaded into some kind of a tit-for-tat feud.
"Thankfully they have also said they will not be drawn, and we hope that remains the case.
"No one wants to see any kind of retaliation of any sort, it is very antagonistic but the people behind this are not on the same page as the rest of the city."
Sinn Fein MLA Raymond McCartney condemned the graffiti also.
The Foyle MLA said: "There can be no place for sectarianism in our society. Sinn Fein condemns any attempt to stoke tensions within communities.
"Everyone should be able to live free from fear or intimidation. If anyone has information about these incidents they should contact the PSNI."
SDLP councillor Martin Reilly said: "I would wholeheartedly condemn any attempt to heighten tensions."
PSNI Inspector Ray Wilson said enquiries were ongoing. He urged anyone with information to contact police at Strand Road on 101, quoting reference number 595 30/07/17.