Phony signs promoting Donald Trump's new golf course have cropped up along Los Angeles freeways, stumping transportation officials and Trump executives alike.

Commuters first spotted the fake signs for the Trump National Golf Club in Rancho Palos Verdes a week ago. Since then, California Department of Transportation workers have pulled down at least four of them.

Most mimic the green freeway directional signs common throughout California.

Click here for the Donald Trump Celebrity Center.

Mike van der Goes, the golf club's general manager, said Trump has denied any involvement.

"We have no idea who put them up," van der Goes said Wednesday. "I spoke with Mr. Trump and he knows nothing about them."

Nor do leaders of a guerrilla artist group that some suspected as the likely culprit.

The group, known as Heavy Trash, attracted attention six years ago with mock transportation signs it erected heralding a fictitious subway route called "the Aqua Line."

"We would never support something as wasteful as a new golf course within the Los Angeles Basin," the group said in an e-mail.

The illicit signs have been seen along the Harbor Freeway, near Pacific Coast Highway and next to 405 Freeway ramps.

"If more signs are brought to our attention," said Caltrans spokeswoman Judy Gish, "we will remove them immediately."