WHEAT RIDGE, Colo. -- A billboard showing President Barack Obama wearing a turban has sparked a lot of attention at the Wheat Ridge used car dealership that put it up

The billboard shows a cartoonish Obama grinning, wearing a turban and says, "PRESIDENT or JIHAD?"

Underneath the president's image is a big yellow square with the phrase, "BIRTH CERTIFICATE" in red letters and then "PROVE IT!"

"WAKE UP AMERICA! REMEMBER FT. HOOD!" appear on the bottom. The ad belongs to the Wolf Automotive car dealership and is visible from Interstate 70.

Dealership owner Phil Wolf said putting the sign up was an act of patriotism.

"I'm just passionate about America," said Wolf, a member of the "birther" movement, which questions Mr. Obama's birth place. "I'm asking a question," he added. "What is he? I don't think he's an American, so what is he?"

Wolf said he does not believe the billboard is racist, but conservatives and liberals are calling for Wolf to take the sign down.

"I think it would be good judgement on the part of the people who put up the billboard to take it down," said Dave Kopel, Research Director at the conservative Independence Institute. "There's lots of things I'd criticize President Obama for, but I think it's ridiculous to say he might be a jihadi."

"This billboard is an example of hateful stereotyping," said Anti-Defamation League spokeswoman Joyce Rubin.

The left-leaning advocacy group MoveOn.org and ProgressNow Colorado called the billboard racist and vowed to boycott businesses owned by Wolf Automotive Group until the billboard is removed.

The Wolf Automotive Group has four dealerships located in Colorado, Wyoming and Montana.