SAN FRANCISCO — The video-game industry's decision to give an adults-only rating to the best-selling "Grand Theft Auto: San Andreas" because of explicit sexual content could signal the start of a crackdown on raunchy games.

The rating change followed intense pressure from politicians and media-watch groups. Retailers reacted swiftly: Wal-Mart Stores Inc., Target Corp. and Best Buy Co. said yesterday they would pull all copies from their store shelves nationwide.

Rockstar Games, the producer of "Grand Theft Auto: San Andreas," said it had stopped making the current version of the game, which includes graphic sex scenes that can be unlocked with an Internet download. The game was released in October with an "M" rating, for players 17 and older.

Sen. Hillary Rodham Clinton, D-New York, applauded the change but said she was disturbed that the sexual material appeared on store shelves in the first place. She repeated her request that the Federal Trade Commission investigate video games, and called on the Entertainment Software Rating Board to do more to police game content.

"Apparently the sexual material was embedded in the game. The company admitted that," Clinton said. "The fact remains that the company gamed the ratings system."

Rep. Joe Baca, D-Calif., said this week the video-game industry needed a good dose of government oversight and renewed a call for a law requiring the FTC to determine if the video-game industry's labeling practices are unfair or deceptive.

"Grand Theft Auto: San Andreas" was last year's top console game, selling more than 5.1 million copies in the U.S., according to market analyst NPD Group. Xbox and PC versions were released last month.

Rockstar's parent company, New York-based Take-Two Interactive Software Inc., acknowledged for the first time that the sex scenes were built into the retail version of the game. Company officials previously suggested that a modification created by outsiders added the scenes.

"The editing and finalization of any game is a complicated task and it's not uncommon for unused and unfinished content to remain on the disc," Take-Two spokesman Jim Ankner told the Associated Press.

In a statement, ESRB chief Patricia Vance said the sex scenes were programmed by Rockstar "to be inaccessible to the player." But she also acknowledged that the "credibility and utility" of the industry-run board's initial "M" rating had been "seriously undermined."

Rockstar said it would provide new labels to any retailer willing to keep selling the games and offer a downloadable patch to fix the sexual content in PC versions. The company also is working on a new, more secure version, to be rated "M," for mature.

A computer program known as Hot Coffee allows users to unlock the sex scenes. Such modifications, or "mods," are wildly popular among hard-core game-players, and have been shown to boost game sales. "Half-Life," for example, is still sold years after its release because of a Counter-Strike mod that allows for detailed counter-terrorist shoot'em-up action.

Take-Two president Paul Eibeler said "the decision to re-rate a game based on an unauthorized third-party modification presents a new challenge for parents, the interactive entertainment industry and anyone who distributes or consumes digital content."

The Parents Television Council, one of several media watchdogs that have criticized Rockstar and ESRB, called on the game publisher to recall the game and offer refunds.

"I tip my cap to that first step of showing responsibility," said Tim Winter, the council's executive director. "Phase two needs to be absolutely getting to the bottom of this coding issue. How did it get into that game? How did it get past the ratings board?"

Take-Two said net sales could drop by more than $50 million this quarter, and lowered its financial expectations for the year to set aside funds for returns of the games.