Sony reportedly commissioned the graffiti in seven US cities
A graffiti advertising campaign for Sony's PlayStation Portable (PSP) has triggered a controversy in the US.
Wordless displays showing cartoon characters interacting with the handheld game console have popped up in cities from New York to San Francisco.
But a Philadelphia watchdog says the stealth marketing violates a regulation process in the city, while others have criticised its visual appeal.
A Sony spokeswoman said its portable product was aimed at "urban nomads".
Molly Smith told Wired News internet news site earlier this month that Sony was hiring artists in seven cities to spray-paint the pre-drawn designs.
But in San Francisco, the ads were defaced as it became known that Sony was behind them. "Fony" was written on one.
And in Philadelphia, an official has now faxed a letter to Sony urging the company to cease the ad campaign.
"This really flies in the face of everything we've been trying to do with our anti-blight initiative," Pedro Ramos said, referring to a campaign against illegal or inappropriate billboards in the city.
However, the ads have also drawn praise.
A Philadelphia resident told the Associated Press the concept was "sharp".
"It's all about hip-hop, urban and all that. They're just trying to get into the teenagers' minds," Eddie Torres said.