Calls to boycott virtual band Gorillaz are swelling after graffiti promoting the band's recent album, Humanz, was spray-painted onto the pavement in a Philadelphia Vietnam Veterans Memorial.

As reports, the memorial park's Facebook page posted an image of the "desecrated" walkways on May 2, calling the nine stencils "disgraceful".

"Just when you think you've seen it all, some moron surprises you. Sometime before April 30 some idiot associated with this band put nine stencils on the walkways and desecrated the Memorial with its name and their new album."

Terry Williamson, president of the Philadelphia Vietnam Veterans Memorial Fund, told, "After all these years and the sweat to build the memorial and to refurbish it and to try to recognize the sacrifice of veterans in the Vietnam War, then we get crap like this.

"We consider the whole area to be sacrosanct. It just galls me that someone would choose this location to advertise a band."

Williamson and the Veterans Memorial are calling for Gorillaz's gig on July 13 at Penn's Landing in Philadelphia to be boycotted, and have reported the vandals to police.

Gorillaz have not yet made a statement on the boycott and there is no evidence that they were affiliated with the vandals.