Motorola has been accused of posting "offensive and irresponsible" adverts that glamorise knife-related violence.
The Advertising Standards Agency received complaints after the mobile firm ran a national press ad and three posters for its Razr 2 handset.
The press ad appeared in The Daily Telegraph and showed a woman wearing PVC clothes.
She was styled like a Samurai warrior and was standing with her hands clasped in front of her, holding a mobile phone at an angle so that it resembled a knife.
The text accompanying the advert stated: 'Music to your ears. External music controls. Stereo Bluetooth Razr 2. Sharper than ever.' The '2' was shaped like a knife slash.
The first poster showed a man and woman facing each other posing in 'fighting' positions. They were both wearing PVC clothes and held mobile phones at an angle, so that they resembled knives.
The man wore headphones and had a tattoo on his upper arm shaped in the form of a knife slash resembling the number two.
A second poster showed the same man holding a mobile phone at an angle so that it resembled a knife. He wore headphones and his tattoo was visible. He posed in a stance as if he were ready to fight.
A third poster, on London Underground escalator panels, showed a woman wearing PVC clothes, holding a mobile phone at an angle so that it resembled a knife.
Defending itself against the criticisms Motorola said that the ads were part of a broader Razr 2 campaign which featured highly stylised fantasy characters engaged in fluid dance movements, rather than confrontations.
The company added that the highly stylised images were designed not to be realistic or to present the characters as "aspirational".
In addition the company argued that the current campaign highlighted and reinforced previous marketing messages for the Razr phone, relating to the 'razor' thinness and the fact that the phone represented a device that is at the cutting edge of technology.
"Motorola believed the ads did not condone or glorify knife violence because they made no reference to knives or violence and the campaign was not about depicting or encouraging physical harm," said the ASA in its ruling.
"It said it was clear that the fantasy characters in the ads were holding mobile phones, not knives. It added that the man's tattoo was not intended to be a depiction of a knife slash and clearly represented the signature '2' from the Razr 2 logo."
After considering the evidence the ASA backed Motorola and refused to uphold the complaints.
The watchdog considered that most readers would appreciate that the ads were promoting the Razr 2 and would understand the link between the image of the phone, which when held at an angle resembled a razor, and the name of the product.
"We agreed that the characters were highly stylised but disagreed with Motorola that the ads made no reference to knives. Although no direct reference was made the intended link that the product resembled a razor, a knife-like object, was clear," the ASA stated.
"Although the models used in the ads were glamorous and the phone was being advertised as a razor-like product we did not think the ads either glamorised or condoned real violence.
"The characters looked fantastical and were not representative of today's culture. We considered that most readers would not see the images as promoting violence or giving the message that violence was to be, in any way, condoned.
"We concluded that the ads were not irresponsible and were unlikely to cause serious or widespread offence."
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