A series of portraits of American soldiers set to adorn roadside billboards in Minneapolis, site of next week's Republican convention, was abruptly cancelled by the billboards' owners, which feared they would be deemed disrespectful to the US military.

Although the artworks neither display images of violence nor are gruesome, the media company that owns the billboards said it feared pedestrians and motorists would mistake them for images of war dead.

The photographs show the faces and close-cropped heads of nine youthful soldiers lying peaceful and prone, flat against a surface.

"They don't look dead," said Suzanne Opton, the photographer of the series, entitled Soldiers' Faces.

"It's like you see someone opposite of you with their head on the pillow. We see our lovers and our children in that pose. They look like the heads of fallen statues, and they afford the viewer an intimate look at the face of the young person whose life is at risk, and that was the point.

"When you see soldiers on the news you have no idea who they are. They're representing the United States and they have all that gear on. I wanted to get past all that".

The shots of troops in between deployments to Iraq and Afghanistan by a New York City artist were to run in five US cities.

But CBS Outdoor abruptly changed course and has refused to post the billboards in Minneapolis, Miami, Florida; and Houston, Texas. A separate company has agreed to display the images on billboards in Atlanta. Curiously for the artists, the images remain up in Denver, site of this week's Democratic national convention.

The Democratic party, under presidential nominee Barack Obama, is against the war in Iraq and advocates withdrawing US combat forces.

When thousands of Republicans and hoards of journalists arrive in the Minneapolis area this weekend, they will not see the images as they shuttle between the Xcel Energy Centre, site of the convention proceedings, and the hotels, restaurants and parties accommodating them.

"We understand that 'Soldier' represents a political art project, and that the individuals depicted are actual soldiers," Jodi Senese, CBS Outdoor's executive vice-president of marketing, wrote in an e-mail to Susan Reynolds, a curator and collaborator with Opton.

"Out of context [neither in a museum setting or website] the images, as stand-alone highway or city billboards, appear to be deceased soldiers. The presentation in this manner could be perceived as being disrespectful to the men and women in our armed forces."

Senese acknowledged in her email that the decision was based not on the artist's intent but "how the image would be perceived by a motorist passing it in transit".

Senese did not immediately return calls seeking comment.

Opton and Reynolds insist the work is neither a partisan statement nor does it advocate against the wars in Iraq and Afghanistan.

"Any time you talk about a war, it's political," Opton said. "It's not an anti-war statement, it's about soldiers."

The photographs were taken in 2004 and 2005 at Fort Drum in New York state, with the permission of the soldiers and their commanders, the collaborators said.

The images have been shown in the Brooklyn Museum, the Cleveland (Ohio) Museum of Art, and the Museum of Fine Arts in Houston. The project is sponsored by the New York Foundation for the Arts. Opton said the photographs ran on billboards in Syracuse, New York, near where the soldiers were based.

In early August the foundation signed a contract to pay CBS Outdoor $5,000 to run images on five billboards in Minneapolis for about a month beginning on Monday. Last week the company cancelled that contracts there, in Houston and Miami, Reynolds said.

Reynolds said CBS Outdoor, which is owned by CBS Corporation, owner of the US television network, wants to avoid controversy.

"I've been censored," Reynolds said.

"It's not a strong advocacy for any partisan point of view. We don't see soldiers in this very individualised human way in the press or media in this country. A soldier is one thing: They're in camouflage, holding a rifle. Here they're individuals with personalities."