LOS ANGELES — CKE Restaurants Inc., the parent company of the Carl's Jr. and Hardee's fast food chains, wants a federal court to order rival Jack in the Box Inc. to stop suggesting that CKE uses cow anus to make its Angus beef burgers.

CKE sued Jack in the Box in U.S. District Court yesterday over two TV ads, including one in which executives laugh hysterically at the word "Angus" and another where the chain's mascot, Jack — a man with the round clown head and pointy nose — is asked to point to a diagram of a cow and show where Angus meat comes from.

"I'd rather not," Jack replies.

The employee asking the question traces a circle in the air with his pen while pronouncing the word Angus.

The lawsuit claims the ads create the misleading impression that Jack in the Box's new 100 percent sirloin hamburgers use a better quality of meat than the Angus beef used by Carl's Jr. and Hardee's.

The lawsuit claims the TV spots confuse consumers by comparing sirloin, a cut of meat found on all cattle, with Angus, which is a breed of cattle. It asks the court to issue a preliminary injunction.

Executives at San Diego-based Jack in the Box had not seen the lawsuit and could not respond, company spokeswoman Kathleen Anthony said.

Restaurants owned by Burger King Holdings Inc. and McDonald's Corp. also serve Angus beef burgers.

CKE is known for running often controversial ads, including one featuring a scantily clad Paris Hilton washing a car while eating a hamburger.

Jack in the Box also runs humorous ads featuring the pingpong-headed Jack. But CKE claims the "Angus" ads have gone too far.

"They're not being funny," CKE chief executive Andrew F. Puzder said yesterday. "They need to stop misleading people about what Angus beef is."

Puzder said the company asked Jack in the Box to drop the ads, but that the chain refused, pointing to a Carl's Jr. TV spot showing a man shoving a cow, suggesting that Carl's Jr. milk shakes were superior to ones served by competitors.

Puzder said the comparison was not valid because the Carl's Jr. ads did not suggest that Jack in the Box milk shakes were made from milk that came from an unsavory part of the cow.