When reviews of Boot Camp came out, it was called "Survivor in fatigues," and now CBS is filing a lawsuit claiming that Fox's show is a rip-off of the No. 1-rated reality show Survivor.

The lawsuit contends that Boot Camp has violated federal copyright law and California state law by mimicking significant elements of the CBS program.

The suit, filed Monday in federal court in Los Angeles, seeks unspecified monetary damages and changes in Boot Camp, which was 24th in last week's Nielsen ratings. Fox and Boot Camp producer LMNO Productions Inc. are among those named as defendants.

"All in all, aside from its military setting, the premise and format of Boot Camp are virtually identical to Survivor," alleges the suit filed on behalf of CBS and Survivor creator Mark Burnett.

"There is absolutely no basis for the claims made by CBS and Mark Burnett," Fox said in a statement Tuesday. "The shows are very different and we believe this is a frivolous lawsuit."

LMNO Productions said it had not been served with the complaint and had no comment.

CBS' action was deemed surprising by one veteran industry analyst.

"Network television is the greatest copycat medium. As soon as someone has a hit of some sort, other networks are trying to make as close a copy as they can," said Paul Schulman of the media buying firm Schulman/Advanswers.

"I don't think CBS has a patent on the reality genre," Schulman added. ABC's Who Wants to Be a Millionaire generated a flood of quiz shows, including Winning Lines on CBS, he noted.

The lawsuit alleges LMNO Productions initially pitched the show to CBS Television President Leslie Moonves in June 2000 as a way to capitalize on the success of Survivor.

In Boot Camp, contestants vying for a cash prize were to be voted off by drill instructors, the suit claims. When CBS rejected the show, LMNO tailored Boot Camp more closely to Survivor, including giving voting rights to contestants, the suit says.

LMNO also hired Scott Messick, a producer of the first Survivor, as director and executive producer of Boot Camp, according to the suit.

To support its argument, the suit offers several newspaper reviews and articles that appeared after Boot Camp debuted March 29, including one that called it "Survivor in fatigues."

The reality genre seems to be a breeding ground for lawsuits. At Fox, two contestants from its Temptation Island are seeking damages over the way they were removed from the show. CBS has been hit with a lawsuit from former Survivor contestant Stacey Stillman, who claimed the game was rigged against her. CBS has countersued Stillman.